diff --git a/packages/at_client/lib/src/at_collection/impl/collection_methods_impl.dart b/packages/at_client/lib/src/at_collection/impl/collection_methods_impl.dart
index 20d94f462..139b30c4d 100644
--- a/packages/at_client/lib/src/at_collection/impl/collection_methods_impl.dart
+++ b/packages/at_client/lib/src/at_collection/impl/collection_methods_impl.dart
@@ -41,7 +41,7 @@ class AtCollectionMethodImpl {
     _logger.finest('Self key to be used : $atKey');
     var atOperationItemStatus = AtOperationItemStatus(
         atSign: atKey.sharedBy ?? '',
-        key: atKey.key ?? '',
+        key: atKey.key,
         complete: false,
         operation: Operation.save);
     try {
@@ -76,7 +76,7 @@ class AtCollectionMethodImpl {
       _logger.finest('Update shared key $sharedKey');
       var atOperationItemStatus = AtOperationItemStatus(
           atSign: sharedKey.sharedWith ?? '',
-          key: sharedKey.key ?? '',
+          key: sharedKey.key,
           complete: false,
           operation: Operation.share);
       try {
@@ -133,7 +133,7 @@ class AtCollectionMethodImpl {
 
       var atOperationItemStatus = AtOperationItemStatus(
           atSign: atSign,
-          key: selfKey.key ?? '',
+          key: selfKey.key,
           complete: false,
           operation: Operation.share);
 
@@ -164,7 +164,7 @@ class AtCollectionMethodImpl {
 
     yield AtOperationItemStatus(
         atSign: selfAtKey.sharedWith ?? '',
-        key: selfAtKey.key ?? '',
+        key: selfAtKey.key,
         complete: isSelfKeyDeleted,
         operation: Operation.delete);
   }
@@ -192,7 +192,7 @@ class AtCollectionMethodImpl {
     for (var sharedKey in sharedAtKeys) {
       var atOperationItemStatus = AtOperationItemStatus(
           atSign: sharedKey.sharedWith ?? '',
-          key: sharedKey.key ?? '',
+          key: sharedKey.key,
           complete: false,
           operation: Operation.unshare);
 
diff --git a/packages/at_client/lib/src/at_collection/impl/default_key_maker.dart b/packages/at_client/lib/src/at_collection/impl/default_key_maker.dart
index 4ce67117b..52782e036 100644
--- a/packages/at_client/lib/src/at_collection/impl/default_key_maker.dart
+++ b/packages/at_client/lib/src/at_collection/impl/default_key_maker.dart
@@ -16,9 +16,9 @@ class DefaultKeyMaker implements KeyMaker {
     return AtKey()
       ..key = '$keyId.$collectionName.atcollectionmodel.$namespace'
       ..metadata = Metadata()
-      ..metadata!.ccd = objectLifeCycleOptions?.cascadeDelete ?? true
-      ..metadata!.ttl = objectLifeCycleOptions?.timeToLive?.inMilliseconds
-      ..metadata!.ttb = objectLifeCycleOptions?.timeToBirth?.inMilliseconds
+      ..metadata.ccd = objectLifeCycleOptions?.cascadeDelete ?? true
+      ..metadata.ttl = objectLifeCycleOptions?.timeToLive?.inMilliseconds
+      ..metadata.ttb = objectLifeCycleOptions?.timeToBirth?.inMilliseconds
       ..sharedBy = _getAtClient().getCurrentAtSign();
   }
 
@@ -36,10 +36,10 @@ class DefaultKeyMaker implements KeyMaker {
       ..key = '$keyId.$collectionName.atcollectionmodel.$namespace'
       ..sharedWith = sharedWith
       ..metadata = Metadata()
-      ..metadata!.ttr = ttrInSeconds ?? -1
-      ..metadata!.ccd = objectLifeCycleOptions?.cascadeDelete ?? true
-      ..metadata!.ttl = objectLifeCycleOptions?.timeToLive?.inMilliseconds
-      ..metadata!.ttb = objectLifeCycleOptions?.timeToBirth?.inMilliseconds
+      ..metadata.ttr = ttrInSeconds ?? -1
+      ..metadata.ccd = objectLifeCycleOptions?.cascadeDelete ?? true
+      ..metadata.ttl = objectLifeCycleOptions?.timeToLive?.inMilliseconds
+      ..metadata.ttb = objectLifeCycleOptions?.timeToBirth?.inMilliseconds
       ..sharedBy = _getAtClient().getCurrentAtSign();
   }
 }
diff --git a/packages/at_client/lib/src/client/at_client_impl.dart b/packages/at_client/lib/src/client/at_client_impl.dart
index 4a8927e05..07b86db39 100644
--- a/packages/at_client/lib/src/client/at_client_impl.dart
+++ b/packages/at_client/lib/src/client/at_client_impl.dart
@@ -294,23 +294,8 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
 
   Future<bool> _delete(AtKey atKey,
       {DeleteRequestOptions? deleteRequestOptions}) async {
-    // If metadata is null, initialize metadata
-    atKey.metadata ??= Metadata();
-    String keyWithNamespace;
-    if (atKey.metadata!.namespaceAware) {
-      keyWithNamespace = AtClientUtil.getKeyWithNameSpace(atKey, _preference!);
-    } else {
-      keyWithNamespace = atKey.key!;
-    }
     atKey.sharedBy ??= _atSign;
-    var builder = DeleteVerbBuilder()
-      ..isLocal = atKey.isLocal
-      ..isCached = atKey.metadata!.isCached
-      ..isPublic =
-          (atKey.metadata!.isPublic == null) ? false : atKey.metadata!.isPublic!
-      ..sharedWith = atKey.sharedWith
-      ..atKey = keyWithNamespace
-      ..sharedBy = atKey.sharedBy;
+    var builder = DeleteVerbBuilder()..atKey = atKey;
     var secondary = getSecondary();
     if (deleteRequestOptions != null &&
         deleteRequestOptions.useRemoteAtServer) {
@@ -441,10 +426,8 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
   Future<AtResponse> putText(AtKey atKey, String value,
       {PutRequestOptions? putRequestOptions}) async {
     try {
-      // Set the default metadata if not already set.
-      atKey.metadata ??= Metadata();
       // Setting metadata.isBinary to false for putText
-      atKey.metadata!.isBinary = false;
+      atKey.metadata.isBinary = false;
       return await _putInternal(atKey, value, putRequestOptions);
     } on AtException catch (e) {
       throw AtExceptionManager.createException(e);
@@ -456,10 +439,8 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
   Future<AtResponse> putBinary(AtKey atKey, List<int> value,
       {PutRequestOptions? putRequestOptions}) async {
     try {
-      // Set the default metadata if not already set.
-      atKey.metadata ??= Metadata();
       // Setting metadata.isBinary to true for putBinary
-      atKey.metadata!.isBinary = true;
+      atKey.metadata.isBinary = true;
       // Base2e15.encode method converts the List<int> type to String.
       return await _putInternal(
           atKey, Base2e15.encode(value), putRequestOptions);
@@ -470,7 +451,7 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
 
   @visibleForTesting
   ensureLowerCase(AtKey atKey) {
-    if ((atKey.key != null && upperCaseRegex.hasMatch(atKey.key!)) ||
+    if (upperCaseRegex.hasMatch(atKey.key) ||
         (atKey.namespace != null &&
             upperCaseRegex.hasMatch(atKey.namespace!))) {
       _logger.finer('AtKey: ${atKey.toString()} previously contained upper case'
@@ -487,12 +468,12 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
     if (atKey.sharedBy.isNull) {
       atKey.sharedBy = _atSign;
     }
-    if (atKey.metadata!.namespaceAware) {
+    if (atKey.metadata.namespaceAware) {
       atKey.namespace ??= preference?.namespace;
     }
 
     if (preference!.atProtocolEmitted >= Version(2, 0, 0)) {
-      atKey.metadata!.ivNonce ??= EncryptionUtil.generateIV();
+      atKey.metadata.ivNonce ??= EncryptionUtil.generateIV();
     }
     ensureLowerCase(atKey);
 
@@ -521,7 +502,7 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
 
     //Get encryptionPrivateKey for public key to signData
     String? encryptionPrivateKey;
-    if (atKey.metadata!.isPublic != null && atKey.metadata!.isPublic! == true) {
+    if (atKey.metadata.isPublic == true) {
       encryptionPrivateKey = await _localSecondary?.getEncryptionPrivateKey();
     }
     // Transform put request
@@ -543,7 +524,7 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
     }
     // Execute the verb builder
     var putResponse = await secondary.executeVerb(verbBuilder,
-        sync: SyncUtil.shouldSync(atKey.key!));
+        sync: SyncUtil.shouldSync(atKey.key));
     // If putResponse is null or empty, return AtResponse with isError set to true
     if (putResponse == null || putResponse.isEmpty) {
       return AtResponse()..isError = true;
@@ -579,27 +560,17 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
   @override
   Future<bool> putMeta(AtKey atKey) async {
     var updateKey = atKey.key;
-    var metadata = atKey.metadata!;
+    var metadata = atKey.metadata;
     if (metadata.namespaceAware) {
-      updateKey = _getKeyWithNamespace(atKey.key!);
+      updateKey = _getKeyWithNamespace(atKey.key);
     }
-    var sharedWith = atKey.sharedWith;
     var builder = UpdateVerbBuilder();
     builder
-      ..atKey = updateKey
-      ..sharedBy = _atSign
-      ..sharedWith = sharedWith
-      ..ttl = metadata.ttl
-      ..ttb = metadata.ttb
-      ..ttr = metadata.ttr
-      ..ccd = metadata.ccd
-      ..isBinary = metadata.isBinary
-      ..isEncrypted = metadata.isEncrypted
-      ..dataSignature = metadata.dataSignature
+      ..atKey = atKey
       ..operation = AtConstants.updateMeta;
 
     var updateMetaResult = await getSecondary()
-        .executeVerb(builder, sync: SyncUtil.shouldSync(updateKey!));
+        .executeVerb(builder, sync: SyncUtil.shouldSync(updateKey));
     return updateMetaResult != null;
   }
 
@@ -768,9 +739,9 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
           ..key = key
           ..sharedWith = sharedWithAtSign
           ..metadata = Metadata()
-          ..metadata!.ttr = -1
+          ..metadata.ttr = -1
           // file transfer key will be deleted after 30 days
-          ..metadata!.ttl = 2592000000
+          ..metadata.ttl = 2592000000
           ..sharedBy = _atSign;
 
         var notificationResult = await notificationService.notify(
@@ -949,7 +920,7 @@ class AtClientImpl implements AtClient, AtSignChangeListener {
       PriorityEnum? priority,
       StrategyEnum? strategy,
       int? latestN,
-      String? notifier = SYSTEM,
+      String? notifier = AtConstants.system,
       bool isDedicated = false}) async {
     AtKeyValidators.get().validate(
         atKey.toString(),
diff --git a/packages/at_client/lib/src/client/local_secondary.dart b/packages/at_client/lib/src/client/local_secondary.dart
index 86881ef91..d1fb0918c 100644
--- a/packages/at_client/lib/src/client/local_secondary.dart
+++ b/packages/at_client/lib/src/client/local_secondary.dart
@@ -69,46 +69,15 @@ class LocalSecondary implements Secondary {
       var updateKey = builder.buildKey();
       switch (builder.operation) {
         case AtConstants.updateMeta:
-          var metadata = Metadata();
-          metadata
-            ..ttl = builder.ttl
-            ..ttb = builder.ttb
-            ..ttr = builder.ttr
-            ..ccd = builder.ccd
-            ..isBinary = builder.isBinary
-            ..isEncrypted = builder.isEncrypted
-            ..sharedKeyEnc = builder.sharedKeyEncrypted
-            ..pubKeyCS = builder.pubKeyChecksum
-            ..encoding = builder.encoding
-            ..encKeyName = builder.encKeyName
-            ..encAlgo = builder.encAlgo
-            ..ivNonce = builder.ivNonce
-            ..skeEncKeyName = builder.skeEncKeyName
-            ..skeEncAlgo = builder.skeEncAlgo;
-          var atMetadata = AtMetaData.fromCommonsMetadata(metadata);
+          var atMetadata =
+              AtMetaData.fromCommonsMetadata(builder.atKey.metadata);
           updateResult = await keyStore!.putMeta(updateKey, atMetadata);
           break;
         default:
           var atData = AtData();
           atData.data = builder.value;
-          var metadata = Metadata();
-          metadata
-            ..ttl = builder.ttl
-            ..ttb = builder.ttb
-            ..ttr = builder.ttr
-            ..ccd = builder.ccd
-            ..isBinary = builder.isBinary
-            ..isEncrypted = builder.isEncrypted
-            ..dataSignature = builder.dataSignature
-            ..sharedKeyEnc = builder.sharedKeyEncrypted
-            ..pubKeyCS = builder.pubKeyChecksum
-            ..encoding = builder.encoding
-            ..encKeyName = builder.encKeyName
-            ..encAlgo = builder.encAlgo
-            ..ivNonce = builder.ivNonce
-            ..skeEncKeyName = builder.skeEncKeyName
-            ..skeEncAlgo = builder.skeEncAlgo;
-          var atMetadata = AtMetaData.fromCommonsMetadata(metadata);
+          var atMetadata =
+              AtMetaData.fromCommonsMetadata(builder.atKey.metadata);
           updateResult = await keyStore!.putAll(updateKey, atData, atMetadata);
           break;
       }
diff --git a/packages/at_client/lib/src/client/verb_builder_manager.dart b/packages/at_client/lib/src/client/verb_builder_manager.dart
index d28b0c3b9..1d6a29490 100644
--- a/packages/at_client/lib/src/client/verb_builder_manager.dart
+++ b/packages/at_client/lib/src/client/verb_builder_manager.dart
@@ -10,12 +10,11 @@ class LookUpBuilderManager {
       {GetRequestOptions? getRequestOptions}) {
     // If isPublic is true in metadata, the key is a public key, return PLookupVerbHandler.
     if (atKey.sharedBy != currentAtSign &&
-        (atKey.metadata != null &&
-            atKey.metadata!.isPublic! &&
-            !atKey.metadata!.isCached)) {
+        (atKey.metadata.isPublic && !atKey.metadata.isCached)) {
       final plookUpVerbBuilder = PLookupVerbBuilder()
-        ..atKey = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
-        ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
+        ..atKey = (AtKey()
+          ..key = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
+          ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy))
         ..operation = 'all';
       if (getRequestOptions != null && getRequestOptions.bypassCache == true) {
         plookUpVerbBuilder.bypassCache = true;
@@ -24,12 +23,11 @@ class LookUpBuilderManager {
     }
     // If sharedBy is not equal to currentAtSign and isCached is false, return LookupVerbHandler
     if (atKey.sharedBy != currentAtSign &&
-        (atKey.metadata != null &&
-            !atKey.metadata!.isCached &&
-            !atKey.metadata!.isPublic!)) {
+        (!atKey.metadata.isCached && !atKey.metadata.isPublic)) {
       final lookupVerbBuilder = LookupVerbBuilder()
-        ..atKey = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
-        ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
+        ..atKey = (AtKey()
+          ..key = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
+          ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy))
         ..auth = true
         ..operation = 'all';
       if (getRequestOptions != null && getRequestOptions.bypassCache == true) {
@@ -38,16 +36,14 @@ class LookUpBuilderManager {
       return lookupVerbBuilder;
     }
     return LLookupVerbBuilder()
-      ..atKey = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
-      ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
-      ..sharedWith = AtClientUtil.fixAtSign(atKey.sharedWith)
-      ..isPublic = (atKey.metadata != null && atKey.metadata?.isPublic != null)
-          ? atKey.metadata!.isPublic!
-          : false
-      ..isCached = (atKey.metadata != null && atKey.metadata?.isCached != null)
-          ? atKey.metadata!.isCached
-          : false
-      ..isLocal = atKey.isLocal
+      ..atKey = (AtKey()
+        ..key = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
+        ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
+        ..sharedWith = AtClientUtil.fixAtSign(atKey.sharedWith)
+        ..metadata = (Metadata()
+          ..isPublic = atKey.metadata.isPublic
+          ..isCached = atKey.metadata.isCached)
+        ..isLocal = atKey.isLocal)
       ..operation = 'all';
   }
 }
diff --git a/packages/at_client/lib/src/decryption_service/decryption_manager.dart b/packages/at_client/lib/src/decryption_service/decryption_manager.dart
index 4b0b9fd82..7099fae4e 100644
--- a/packages/at_client/lib/src/decryption_service/decryption_manager.dart
+++ b/packages/at_client/lib/src/decryption_service/decryption_manager.dart
@@ -21,7 +21,7 @@ class AtKeyDecryptionManager {
     // Eg: currentAtSign is @bob and _phone.wavi@bob (or) phone@bob (or) @bob:phone@bob
     if (((atKey.sharedWith == null || atKey.sharedWith == currentAtSign) &&
             atKey.sharedBy == currentAtSign) ||
-        atKey.key!.startsWith('_')) {
+        atKey.key.startsWith('_')) {
       return SelfKeyDecryption(_atClient);
     }
     // Returns LocalKeyDecryption to for the keys present in local storage
diff --git a/packages/at_client/lib/src/decryption_service/local_key_decryption.dart b/packages/at_client/lib/src/decryption_service/local_key_decryption.dart
index 052877fc7..ed6d774fc 100644
--- a/packages/at_client/lib/src/decryption_service/local_key_decryption.dart
+++ b/packages/at_client/lib/src/decryption_service/local_key_decryption.dart
@@ -33,6 +33,6 @@ class LocalKeyDecryption extends AbstractAtKeyEncryption
           exceptionScenario: ExceptionScenario.fetchEncryptionKeys);
     }
     return EncryptionUtil.decryptValue(encryptedValue, symmetricKey,
-        ivBase64: atKey.metadata?.ivNonce);
+        ivBase64: atKey.metadata.ivNonce);
   }
 }
diff --git a/packages/at_client/lib/src/decryption_service/self_key_decryption.dart b/packages/at_client/lib/src/decryption_service/self_key_decryption.dart
index 752073150..63bc4b025 100644
--- a/packages/at_client/lib/src/decryption_service/self_key_decryption.dart
+++ b/packages/at_client/lib/src/decryption_service/self_key_decryption.dart
@@ -31,6 +31,6 @@ class SelfKeyDecryption implements AtKeyDecryption {
 
     return EncryptionUtil.decryptValue(encryptedValue,
         DefaultResponseParser().parse(selfEncryptionKey).response,
-        ivBase64: atKey.metadata?.ivNonce);
+        ivBase64: atKey.metadata.ivNonce);
   }
 }
diff --git a/packages/at_client/lib/src/decryption_service/shared_key_decryption.dart b/packages/at_client/lib/src/decryption_service/shared_key_decryption.dart
index 120fc671c..4a359f372 100644
--- a/packages/at_client/lib/src/decryption_service/shared_key_decryption.dart
+++ b/packages/at_client/lib/src/decryption_service/shared_key_decryption.dart
@@ -31,8 +31,8 @@ class SharedKeyDecryption implements AtKeyDecryption {
           exceptionScenario: ExceptionScenario.decryptionFailed);
     }
     String? encryptedSharedKey;
-    if (atKey.metadata != null && atKey.metadata!.pubKeyCS != null) {
-      encryptedSharedKey = atKey.metadata!.sharedKeyEnc;
+    if (atKey.metadata.pubKeyCS != null) {
+      encryptedSharedKey = atKey.metadata.sharedKeyEnc;
       String? currentAtSignPublicKey;
       try {
         currentAtSignPublicKey = (await atClient
@@ -46,7 +46,7 @@ class SharedKeyDecryption implements AtKeyDecryption {
             exceptionScenario: ExceptionScenario.localVerbExecutionFailed);
       }
       if (currentAtSignPublicKey != null &&
-          atKey.metadata!.pubKeyCS !=
+          atKey.metadata.pubKeyCS !=
               EncryptionUtil.md5CheckSum(currentAtSignPublicKey)) {
         throw AtPublicKeyChangeException(
             'Public key has changed. Cannot decrypt shared key ${atKey.toString()}',
@@ -69,7 +69,7 @@ class SharedKeyDecryption implements AtKeyDecryption {
           .decryptString(encryptedSharedKey, EncryptionKeyType.rsa2048);
       decryptedValue = EncryptionUtil.decryptValue(
           encryptedValue, decryptionResult.result,
-          ivBase64: atKey.metadata?.ivNonce);
+          ivBase64: atKey.metadata.ivNonce);
     } on AtKeyException catch (e) {
       e.stack(AtChainedException(
           Intent.decryptData,
@@ -83,10 +83,11 @@ class SharedKeyDecryption implements AtKeyDecryption {
   Future<String> _getEncryptedSharedKey(AtKey atKey) async {
     String? encryptedSharedKey = '';
     var localLookupSharedKeyBuilder = LLookupVerbBuilder()
-      ..atKey = AtConstants.atEncryptionSharedKey
-      ..sharedWith = atClient.getCurrentAtSign()
-      ..sharedBy = atKey.sharedBy
-      ..isCached = true;
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedWith = atClient.getCurrentAtSign()
+        ..sharedBy = atKey.sharedBy
+        ..metadata = (Metadata()..isCached = true));
     try {
       encryptedSharedKey = await atClient
           .getLocalSecondary()!
@@ -99,8 +100,9 @@ class SharedKeyDecryption implements AtKeyDecryption {
         encryptedSharedKey.isEmpty ||
         encryptedSharedKey == 'data:null') {
       var sharedKeyLookUpBuilder = LookupVerbBuilder()
-        ..atKey = AtConstants.atEncryptionSharedKey
-        ..sharedBy = atKey.sharedBy
+        ..atKey = (AtKey()
+          ..key = AtConstants.atEncryptionSharedKey
+          ..sharedBy = atKey.sharedBy)
         ..auth = true;
       encryptedSharedKey = await atClient
           .getRemoteSecondary()!
diff --git a/packages/at_client/lib/src/encryption_service/abstract_atkey_encryption.dart b/packages/at_client/lib/src/encryption_service/abstract_atkey_encryption.dart
index 85d581f23..3e4342eec 100644
--- a/packages/at_client/lib/src/encryption_service/abstract_atkey_encryption.dart
+++ b/packages/at_client/lib/src/encryption_service/abstract_atkey_encryption.dart
@@ -49,8 +49,8 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
         await verifyTheirCopyOfSharedSymmetricKey(atKey, _sharedKey);
 
     if (storeSharedKeyEncryptedWithData) {
-      atKey.metadata!.sharedKeyEnc = theirEncryptedSymmetricKeyCopy;
-      atKey.metadata!.pubKeyCS =
+      atKey.metadata.sharedKeyEnc = theirEncryptedSymmetricKeyCopy;
+      atKey.metadata.pubKeyCS =
           EncryptionUtil.md5CheckSum(await _getSharedWithPublicKey(atKey));
     }
   }
@@ -248,10 +248,12 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
     try {
       // 1. Get the cached public key
       var cachedEncryptionPublicKeyBuilder = LLookupVerbBuilder()
-        ..atKey = 'publickey'
-        ..sharedBy = atKey.sharedWith
-        ..isPublic = true
-        ..isCached = true;
+        ..atKey = (AtKey()
+          ..key = 'publickey'
+          ..sharedBy = atKey.sharedWith
+          ..metadata = (Metadata()
+            ..isPublic = true
+            ..isCached = true));
 
       sharedWithPublicKey = await _atClient
           .getLocalSecondary()!
@@ -262,8 +264,9 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
     try {
       if (sharedWithPublicKey.isNull || sharedWithPublicKey == 'data:null') {
         var encryptionPublicKeyBuilder = PLookupVerbBuilder()
-          ..atKey = 'publickey'
-          ..sharedBy = atKey.sharedWith;
+          ..atKey = (AtKey()
+            ..key = 'publickey'
+            ..sharedBy = atKey.sharedWith);
         sharedWithPublicKey = await _atClient
             .getRemoteSecondary()!
             .executeVerb(encryptionPublicKeyBuilder);
@@ -286,9 +289,10 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
   Future<void> _storeMyEncryptedCopyOfSharedSymmetricKey(
       AtKey atKey, String encryptedSharedKey, Secondary secondary) async {
     var updateSharedKeyForCurrentAtSignBuilder = UpdateVerbBuilder()
-      ..atKey =
-          '${AtConstants.atEncryptionSharedKey}.${atKey.sharedWith?.replaceAll('@', '')}'
-      ..sharedBy = atKey.sharedBy
+      ..atKey = (AtKey()
+        ..key =
+            '${AtConstants.atEncryptionSharedKey}.${atKey.sharedWith?.replaceAll('@', '')}'
+        ..sharedBy = atKey.sharedBy)
       ..value = encryptedSharedKey;
     await secondary.executeVerb(updateSharedKeyForCurrentAtSignBuilder,
         sync: false);
@@ -300,9 +304,10 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
   Future<String?> _getMyEncryptedCopyOfSharedSymmetricKey(
       Secondary secondary, AtKey atKey) async {
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey =
-          '${AtConstants.atEncryptionSharedKey}.${atKey.sharedWith?.replaceAll('@', '')}'
-      ..sharedBy = atKey.sharedBy;
+      ..atKey = (AtKey()
+        ..key =
+            '${AtConstants.atEncryptionSharedKey}.${atKey.sharedWith?.replaceAll('@', '')}'
+        ..sharedBy = atKey.sharedBy);
     String? myCopy;
 
     try {
@@ -324,9 +329,10 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
   Future<String?> _getTheirEncryptedCopyOfSharedSymmetricKey(
       Secondary secondary, AtKey atKey) async {
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = AtConstants.atEncryptionSharedKey
-      ..sharedBy = atKey.sharedBy
-      ..sharedWith = atKey.sharedWith;
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedBy = atKey.sharedBy
+        ..sharedWith = atKey.sharedWith);
     String? theirCopy;
     try {
       theirCopy = await secondary.executeVerb(llookupVerbBuilder);
@@ -346,10 +352,11 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
       {Secondary? secondary}) async {
     secondary ??= _atClient.getLocalSecondary()!;
     var updateSharedKeyBuilder = UpdateVerbBuilder()
-      ..atKey = AtConstants.atEncryptionSharedKey
-      ..sharedWith = atKey.sharedWith
-      ..sharedBy = atKey.sharedBy
-      ..ttr = 3888000
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedWith = atKey.sharedWith
+        ..sharedBy = atKey.sharedBy
+        ..metadata = (Metadata()..ttr = 3888000))
       ..value = encryptedSharedKeyValue;
     return await secondary.executeVerb(updateSharedKeyBuilder, sync: false);
   }
@@ -360,9 +367,10 @@ abstract class AbstractAtKeyEncryption implements AtKeyEncryption {
   Future<void> deleteTheirCopyOfEncryptedSharedKey(
       AtKey atKey, Secondary secondary) async {
     var deleteBuilder = DeleteVerbBuilder()
-      ..atKey = AtConstants.atEncryptionSharedKey
-      ..sharedWith = atKey.sharedWith
-      ..sharedBy = atKey.sharedBy;
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedWith = atKey.sharedWith
+        ..sharedBy = atKey.sharedBy);
 
     _logger.info(
         'Deleting ${deleteBuilder.buildKey()} from ${secondary.runtimeType}');
diff --git a/packages/at_client/lib/src/encryption_service/self_key_encryption.dart b/packages/at_client/lib/src/encryption_service/self_key_encryption.dart
index b2f9ee3ed..6545f3c26 100644
--- a/packages/at_client/lib/src/encryption_service/self_key_encryption.dart
+++ b/packages/at_client/lib/src/encryption_service/self_key_encryption.dart
@@ -34,7 +34,7 @@ class SelfKeyEncryption implements AtKeyEncryption {
         DefaultResponseParser().parse(selfEncryptionKey).response;
     // Encrypt value using sharedKey
     return EncryptionUtil.encryptValue(value, selfEncryptionKey,
-        ivBase64: atKey.metadata?.ivNonce);
+        ivBase64: atKey.metadata.ivNonce);
   }
 
   Future<String> _getSelfEncryptionKey(LocalSecondary localSecondary) async {
diff --git a/packages/at_client/lib/src/encryption_service/shared_key_encryption.dart b/packages/at_client/lib/src/encryption_service/shared_key_encryption.dart
index 631da68c7..7fc1cfaab 100644
--- a/packages/at_client/lib/src/encryption_service/shared_key_encryption.dart
+++ b/packages/at_client/lib/src/encryption_service/shared_key_encryption.dart
@@ -20,6 +20,6 @@ class SharedKeyEncryption extends AbstractAtKeyEncryption {
 
     // Encrypt the value
     return EncryptionUtil.encryptValue(value, sharedKey,
-        ivBase64: atKey.metadata?.ivNonce);
+        ivBase64: atKey.metadata.ivNonce);
   }
 }
diff --git a/packages/at_client/lib/src/encryption_service/sign_in_public_data.dart b/packages/at_client/lib/src/encryption_service/sign_in_public_data.dart
index 06b9fa72e..abbd74f80 100644
--- a/packages/at_client/lib/src/encryption_service/sign_in_public_data.dart
+++ b/packages/at_client/lib/src/encryption_service/sign_in_public_data.dart
@@ -1,5 +1,4 @@
 import 'dart:convert';
-import 'dart:typed_data';
 
 import 'package:crypton/crypton.dart';
 
@@ -10,8 +9,7 @@ class SignInPublicData {
   static Future<String> signInData(
       dynamic value, String encryptedPrivateKey) async {
     var privateKey = RSAPrivateKey.fromString(encryptedPrivateKey);
-    var dataSignature =
-        privateKey.createSHA256Signature(utf8.encode(value) as Uint8List);
+    var dataSignature = privateKey.createSHA256Signature(utf8.encode(value));
     return base64Encode(dataSignature);
   }
 }
diff --git a/packages/at_client/lib/src/encryption_service/stream_encryption.dart b/packages/at_client/lib/src/encryption_service/stream_encryption.dart
index dbe3daa6b..78a9ab78c 100644
--- a/packages/at_client/lib/src/encryption_service/stream_encryption.dart
+++ b/packages/at_client/lib/src/encryption_service/stream_encryption.dart
@@ -18,6 +18,6 @@ class StreamEncryption extends AbstractAtKeyEncryption {
         storeSharedKeyEncryptedWithData: storeSharedKeyEncryptedWithData);
     // Encrypt value using sharedKey
     return EncryptionUtil.encryptBytes(value, sharedKey,
-        ivBase64: atKey.metadata?.ivNonce);
+        ivBase64: atKey.metadata.ivNonce);
   }
 }
diff --git a/packages/at_client/lib/src/key_stream/key_stream_iterable_base.dart b/packages/at_client/lib/src/key_stream/key_stream_iterable_base.dart
index 8a46391bb..4e9c2b5c5 100644
--- a/packages/at_client/lib/src/key_stream/key_stream_iterable_base.dart
+++ b/packages/at_client/lib/src/key_stream/key_stream_iterable_base.dart
@@ -53,7 +53,7 @@ class KeyStreamIterableBase<T, I extends Iterable<T>> extends KeyStreamMixin<I>
     FutureOr<void> Function(Object exception, [StackTrace? stackTrace])?
         onError,
     AtClientManager? atClientManager,
-  })  : _generateRef = generateRef ?? ((key, value) => key.key ?? ''),
+  })  : _generateRef = generateRef ?? ((key, value) => key.key),
         _castTo = castTo ?? ((Iterable<T> values) => values as I),
         super(
           convert: convert,
diff --git a/packages/at_client/lib/src/key_stream/key_stream_map_base.dart b/packages/at_client/lib/src/key_stream/key_stream_map_base.dart
index f58e05e10..cd9e44838 100644
--- a/packages/at_client/lib/src/key_stream/key_stream_map_base.dart
+++ b/packages/at_client/lib/src/key_stream/key_stream_map_base.dart
@@ -43,7 +43,7 @@ class KeyStreamMapBase<K, V, I extends Map<K, V>> extends KeyStreamMixin<I>
     FutureOr<void> Function(Object exception, [StackTrace? stackTrace])?
         onError,
     AtClientManager? atClientManager,
-  })  : _generateRef = generateRef ?? ((key, value) => key.key ?? ''),
+  })  : _generateRef = generateRef ?? ((key, value) => key.key),
         _castTo = castTo ?? ((Iterable<MapEntry<K, V>> values) => values as I),
         super(
           convert: convert,
diff --git a/packages/at_client/lib/src/manager/sync_manager.dart b/packages/at_client/lib/src/manager/sync_manager.dart
index d8a459d64..08cc2a72c 100644
--- a/packages/at_client/lib/src/manager/sync_manager.dart
+++ b/packages/at_client/lib/src/manager/sync_manager.dart
@@ -204,7 +204,8 @@ class SyncManager {
         .getLastSyncedEntry(_preference!.syncRegex, atSign: _atSign!);
     var lastSyncedCommitId = lastSyncedEntry?.commitId;
     var commitIdReceivePort = ReceivePort();
-    var privateKey = await _localSecondary!.keyStore!.get(AT_PKAM_PRIVATE_KEY);
+    var privateKey =
+        await _localSecondary!.keyStore!.get(AtConstants.atPkamPrivateKey);
     var isolate = await Isolate.spawn(
         SyncIsolateManager.executeRemoteCommandIsolate,
         commitIdReceivePort.sendPort);
@@ -338,7 +339,7 @@ class SyncManager {
         var builder = UpdateVerbBuilder()
           ..atKey = serverCommitEntry['atKey']
           ..value = serverCommitEntry['value'];
-        builder.operation = UPDATE_ALL;
+        builder.operation = AtConstants.updateAll;
         _setMetaData(builder, serverCommitEntry);
         await _pullToLocal(builder, serverCommitEntry, CommitOp.UPDATE_ALL);
         break;
@@ -349,29 +350,33 @@ class SyncManager {
     }
   }
 
-  void _setMetaData(builder, serverCommitEntry) {
+  void _setMetaData(UpdateVerbBuilder builder, serverCommitEntry) {
     var metaData = serverCommitEntry['metadata'];
     if (metaData != null && metaData.isNotEmpty) {
-      if (metaData[AT_TTL] != null) builder.ttl = int.parse(metaData[AT_TTL]);
-      if (metaData[AT_TTB] != null) builder.ttb = int.parse(metaData[AT_TTB]);
-      if (metaData[AT_TTR] != null) builder.ttr = int.parse(metaData[AT_TTR]);
-      if (metaData[CCD] != null) {
-        (metaData[CCD].toLowerCase() == 'true')
-            ? builder.ccd = true
-            : builder.ccd = false;
+      if (metaData[AtConstants.ttl] != null)
+        builder.atKey.metadata.ttl = int.parse(metaData[AtConstants.ttl]);
+      if (metaData[AtConstants.ttb] != null)
+        builder.atKey.metadata.ttb = int.parse(metaData[AtConstants.ttb]);
+      if (metaData[AtConstants.ttr] != null)
+        builder.atKey.metadata.ttr = int.parse(metaData[AtConstants.ttr]);
+      if (metaData[AtConstants.ccd] != null) {
+        (metaData[AtConstants.ccd].toLowerCase() == 'true')
+            ? builder.atKey.metadata.ccd = true
+            : builder.atKey.metadata.ccd = false;
       }
-      if (metaData[PUBLIC_DATA_SIGNATURE] != null) {
-        builder.dataSignature = metaData[PUBLIC_DATA_SIGNATURE];
+      if (metaData[AtConstants.publicDataSignature] != null) {
+        builder.atKey.metadata.dataSignature =
+            metaData[AtConstants.publicDataSignature];
       }
-      if (metaData[IS_BINARY] != null) {
-        (metaData[IS_BINARY].toLowerCase() == 'true')
-            ? builder.isBinary = true
-            : builder.isBinary = false;
+      if (metaData[AtConstants.isBinary] != null) {
+        (metaData[AtConstants.isBinary].toLowerCase() == 'true')
+            ? builder.atKey.metadata.isBinary = true
+            : builder.atKey.metadata.isBinary = false;
       }
-      if (metaData[IS_ENCRYPTED] != null) {
-        (metaData[IS_ENCRYPTED].toLowerCase() == 'true')
-            ? builder.isEncrypted = true
-            : builder.isEncrypted = false;
+      if (metaData[AtConstants.isEncrypted] != null) {
+        (metaData[AtConstants.isEncrypted].toLowerCase() == 'true')
+            ? builder.atKey.metadata.isEncrypted = true
+            : builder.atKey.metadata.isEncrypted = false;
       }
     }
   }
diff --git a/packages/at_client/lib/src/service/encryption_service.dart b/packages/at_client/lib/src/service/encryption_service.dart
index f1ccaf829..6f5cab98d 100644
--- a/packages/at_client/lib/src/service/encryption_service.dart
+++ b/packages/at_client/lib/src/service/encryption_service.dart
@@ -95,8 +95,9 @@ class EncryptionService {
     //a local lookup the cached public key of sharedWith atsign.
     String? sharedWithPublicKey;
     var cachedPublicKeyBuilder = LLookupVerbBuilder()
-      ..atKey = 'publickey.$sharedWithUser'
-      ..sharedBy = atSign;
+      ..atKey = (AtKey()
+        ..key = 'publickey.$sharedWithUser'
+        ..sharedBy = atSign);
     try {
       sharedWithPublicKey =
           await localSecondary!.executeVerb(cachedPublicKeyBuilder);
@@ -112,8 +113,9 @@ class EncryptionService {
 
     //b Lookup public key of sharedWith atsign
     var plookupBuilder = PLookupVerbBuilder()
-      ..atKey = 'publickey'
-      ..sharedBy = sharedWithUser;
+      ..atKey = (AtKey()
+        ..key = 'publickey'
+        ..sharedBy = sharedWithUser);
     sharedWithPublicKey = await remoteSecondary!.executeVerb(plookupBuilder);
     sharedWithPublicKey =
         DefaultResponseParser().parse(sharedWithPublicKey).response;
@@ -125,8 +127,9 @@ class EncryptionService {
     }
     //Cache the sharedWithPublicKey
     var sharedWithPublicKeyBuilder = UpdateVerbBuilder()
-      ..atKey = 'publickey.$sharedWithUser'
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'publickey.$sharedWithUser'
+        ..sharedBy = atSign)
       ..value = sharedWithPublicKey;
     await localSecondary!.executeVerb(sharedWithPublicKeyBuilder, sync: true);
     return sharedWithPublicKey;
@@ -135,8 +138,9 @@ class EncryptionService {
   Future<String?> _getSharedKeyFromLocalForEncryption(String sharedWith) async {
     final sharedWithUser = sharedWith.replaceFirst('@', '');
     final llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
-      ..sharedBy = atSign;
+      ..atKey = (AtKey()
+        ..key = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
+        ..sharedBy = atSign);
     String? sharedKey;
     try {
       sharedKey = await localSecondary!.executeVerb(llookupVerbBuilder);
@@ -151,8 +155,9 @@ class EncryptionService {
       String sharedWith) async {
     final sharedWithUser = sharedWith.replaceFirst('@', '');
     final llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
-      ..sharedBy = atSign;
+      ..atKey = (AtKey()
+        ..key = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
+        ..sharedBy = atSign);
     String? sharedKey;
     try {
       sharedKey = await remoteSecondary!.executeVerb(llookupVerbBuilder);
@@ -166,9 +171,10 @@ class EncryptionService {
     var sharedWithUser = sharedWith.replaceFirst('@', '');
     //Verify if encryptedSharedKey for sharedWith atSign is available.
     var lookupEncryptionSharedKey = LLookupVerbBuilder()
-      ..sharedWith = sharedWith
-      ..sharedBy = atSign
-      ..atKey = AtConstants.atEncryptionSharedKey;
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedWith = sharedWith
+        ..sharedBy = atSign);
     String? result;
     try {
       result = await localSecondary!.executeVerb(lookupEncryptionSharedKey);
@@ -195,11 +201,12 @@ class EncryptionService {
           EncryptionUtil.encryptKey(sharedKey, sharedWithPublicKey);
       // Store the encryptedSharedWith Key. Set ttr to enable sharedWith atsign to cache the encryptedSharedKey.
       var updateSharedKeyBuilder = UpdateVerbBuilder()
-        ..sharedWith = sharedWith
-        ..sharedBy = atSign
-        ..atKey = AtConstants.atEncryptionSharedKey
-        ..value = encryptedSharedKey
-        ..ttr = 3888000;
+        ..atKey = (AtKey()
+          ..key = AtConstants.atEncryptionSharedKey
+          ..sharedWith = sharedWith
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..ttr = 3888000))
+        ..value = encryptedSharedKey;
       await localSecondary!.executeVerb(updateSharedKeyBuilder, sync: true);
     }
   }
@@ -215,8 +222,9 @@ class EncryptionService {
         EncryptionUtil.encryptKey(sharedKey, currentAtSignPublicKey!);
 
     var updateSharedKeyForCurrentAtSignBuilder = UpdateVerbBuilder()
-      ..sharedBy = atSign
-      ..atKey = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
+      ..atKey = (AtKey()
+        ..key = '${AtConstants.atEncryptionSharedKey}.$sharedWithUser'
+        ..sharedBy = atSign)
       ..value = encryptedSharedKeyForCurrentAtSign;
     await localSecondary!
         .executeVerb(updateSharedKeyForCurrentAtSignBuilder, sync: true);
@@ -225,10 +233,11 @@ class EncryptionService {
   Future<String?> _getSharedKeyForDecryption(String sharedBy) async {
     String? encryptedSharedKey;
     var localLookupSharedKeyBuilder = LLookupVerbBuilder()
-      ..isCached = true
-      ..sharedBy = sharedBy
-      ..sharedWith = atSign
-      ..atKey = AtConstants.atEncryptionSharedKey;
+      ..atKey = (AtKey()
+        ..key = AtConstants.atEncryptionSharedKey
+        ..sharedBy = sharedBy
+        ..sharedWith = atSign
+        ..metadata = (Metadata()..isCached = true));
     try {
       encryptedSharedKey =
           await localSecondary!.executeVerb(localLookupSharedKeyBuilder);
@@ -238,8 +247,9 @@ class EncryptionService {
     }
     if (encryptedSharedKey == null || encryptedSharedKey == 'data:null') {
       var sharedKeyLookUpBuilder = LookupVerbBuilder()
-        ..atKey = AtConstants.atEncryptionSharedKey
-        ..sharedBy = sharedBy
+        ..atKey = (AtKey()
+          ..key = AtConstants.atEncryptionSharedKey
+          ..sharedBy = sharedBy)
         ..auth = true;
       encryptedSharedKey =
           await remoteSecondary!.executeVerb(sharedKeyLookUpBuilder);
diff --git a/packages/at_client/lib/src/service/notification_service_impl.dart b/packages/at_client/lib/src/service/notification_service_impl.dart
index 1e9c5ed84..784acf268 100644
--- a/packages/at_client/lib/src/service/notification_service_impl.dart
+++ b/packages/at_client/lib/src/service/notification_service_impl.dart
@@ -327,9 +327,7 @@ class NotificationServiceImpl
       ..atKey = notificationParams.atKey;
 
     if (_atClient.getPreferences()!.atProtocolEmitted >= Version(2, 0, 0)) {
-      notificationParams.atKey.metadata ??= Metadata();
-      notificationParams.atKey.metadata!.ivNonce ??=
-          EncryptionUtil.generateIV();
+      notificationParams.atKey.metadata.ivNonce ??= EncryptionUtil.generateIV();
     }
 
     try {
@@ -410,7 +408,8 @@ class NotificationServiceImpl
       case MessageTypeEnum.text:
         // When messageType is text, the "text" to notify is added to the key. Hence validating
         // the key length
-        if (builder.atKey!.length > _atClient.getPreferences()!.maxDataSize) {
+        if (builder.atKey.key.length >
+            _atClient.getPreferences()!.maxDataSize) {
           throw BufferOverFlowException(
               'The length of value exceeds the maximum allowed length. Maximum buffer size is ${_atClient.getPreferences()!.maxDataSize} bytes. Found ${builder.value.toString().length} bytes');
         }
diff --git a/packages/at_client/lib/src/service/sync/sync_status.dart b/packages/at_client/lib/src/service/sync/sync_status.dart
index 72cce7f2a..656c9508f 100644
--- a/packages/at_client/lib/src/service/sync/sync_status.dart
+++ b/packages/at_client/lib/src/service/sync/sync_status.dart
@@ -1,5 +1,4 @@
 import 'package:at_client/at_client.dart';
-import 'package:at_client/src/service/sync_service_impl.dart';
 
 ///Enum to represent the sync status
 enum SyncStatus { started, notStarted, success, failure }
diff --git a/packages/at_client/lib/src/service/sync_service_impl.dart b/packages/at_client/lib/src/service/sync_service_impl.dart
index 8eefc565f..012f4e6cf 100644
--- a/packages/at_client/lib/src/service/sync_service_impl.dart
+++ b/packages/at_client/lib/src/service/sync_service_impl.dart
@@ -896,7 +896,7 @@ class SyncServiceImpl implements SyncService, AtSignChangeListener {
       case '#':
       case '*':
         var builder = UpdateVerbBuilder()
-          ..atKeyObj = AtKey.fromString(serverCommitEntry['atKey'])
+          ..atKey = AtKey.fromString(serverCommitEntry['atKey'])
           ..value = serverCommitEntry['value'];
         builder.operation = AtConstants.updateAll;
         _setMetaData(builder, serverCommitEntry);
@@ -904,7 +904,7 @@ class SyncServiceImpl implements SyncService, AtSignChangeListener {
         break;
       case '-':
         var builder = DeleteVerbBuilder()
-          ..atKeyObj = AtKey.fromString(serverCommitEntry['atKey']);
+          ..atKey = AtKey.fromString(serverCommitEntry['atKey']);
         await _pullToLocal(builder, serverCommitEntry, CommitOp.DELETE);
         break;
     }
@@ -936,57 +936,60 @@ class SyncServiceImpl implements SyncService, AtSignChangeListener {
     var metaData = serverCommitEntry['metadata'];
     if (metaData != null && metaData.isNotEmpty) {
       if (metaData[AtConstants.ttl] != null) {
-        builder.ttl = int.parse(metaData[AtConstants.ttl]);
+        builder.atKey.metadata.ttl = int.parse(metaData[AtConstants.ttl]);
       }
       if (metaData[AtConstants.ttb] != null) {
-        builder.ttb = int.parse(metaData[AtConstants.ttb]);
+        builder.atKey.metadata.ttb = int.parse(metaData[AtConstants.ttb]);
       }
       if (metaData[AtConstants.ttr] != null) {
-        builder.ttr = int.parse(metaData[AtConstants.ttr]);
+        builder.atKey.metadata.ttr = int.parse(metaData[AtConstants.ttr]);
       }
       if (metaData[AtConstants.ccd] != null) {
         (metaData[AtConstants.ccd].toLowerCase() == 'true')
-            ? builder.ccd = true
-            : builder.ccd = false;
+            ? builder.atKey.metadata.ccd = true
+            : builder.atKey.metadata.ccd = false;
       }
       if (metaData[AtConstants.publicDataSignature] != null) {
-        builder.dataSignature = metaData[AtConstants.publicDataSignature];
+        builder.atKey.metadata.dataSignature =
+            metaData[AtConstants.publicDataSignature];
       }
       if (metaData[AtConstants.isBinary] != null) {
         (metaData[AtConstants.isBinary].toLowerCase() == 'true')
-            ? builder.isBinary = true
-            : builder.isBinary = false;
+            ? builder.atKey.metadata.isBinary = true
+            : builder.atKey.metadata.isBinary = false;
       }
       if (metaData[AtConstants.isEncrypted] != null) {
         (metaData[AtConstants.isEncrypted].toLowerCase() == 'true')
-            ? builder.isEncrypted = true
-            : builder.isEncrypted = false;
+            ? builder.atKey.metadata.isEncrypted = true
+            : builder.atKey.metadata.isEncrypted = false;
       }
       if (metaData[AtConstants.sharedKeyEncrypted] != null) {
-        builder.sharedKeyEncrypted = metaData[AtConstants.sharedKeyEncrypted];
+        builder.atKey.metadata.sharedKeyEnc =
+            metaData[AtConstants.sharedKeyEncrypted];
       }
       if (metaData[AtConstants.sharedWithPublicKeyCheckSum] != null) {
-        builder.pubKeyChecksum =
+        builder.atKey.metadata.pubKeyCS =
             metaData[AtConstants.sharedWithPublicKeyCheckSum];
       }
       if (metaData[AtConstants.encoding] != null) {
-        builder.encoding = metaData[AtConstants.encoding];
+        builder.atKey.metadata.encoding = metaData[AtConstants.encoding];
       }
       if (metaData[AtConstants.encryptingKeyName] != null) {
-        builder.encKeyName = metaData[AtConstants.encryptingKeyName];
+        builder.atKey.metadata.encKeyName =
+            metaData[AtConstants.encryptingKeyName];
       }
       if (metaData[AtConstants.encryptingAlgo] != null) {
-        builder.encAlgo = metaData[AtConstants.encryptingAlgo];
+        builder.atKey.metadata.encAlgo = metaData[AtConstants.encryptingAlgo];
       }
       if (metaData[AtConstants.ivOrNonce] != null) {
-        builder.ivNonce = metaData[AtConstants.ivOrNonce];
+        builder.atKey.metadata.ivNonce = metaData[AtConstants.ivOrNonce];
       }
       if (metaData[AtConstants.sharedKeyEncryptedEncryptingKeyName] != null) {
-        builder.skeEncKeyName =
+        builder.atKey.metadata.skeEncKeyName =
             metaData[AtConstants.sharedKeyEncryptedEncryptingKeyName];
       }
       if (metaData[AtConstants.sharedKeyEncryptedEncryptingAlgo] != null) {
-        builder.skeEncAlgo =
+        builder.atKey.metadata.skeEncAlgo =
             metaData[AtConstants.sharedKeyEncryptedEncryptingAlgo];
       }
     }
diff --git a/packages/at_client/lib/src/transformer/request_transformer/get_request_transformer.dart b/packages/at_client/lib/src/transformer/request_transformer/get_request_transformer.dart
index b4f3a069d..835cb553a 100644
--- a/packages/at_client/lib/src/transformer/request_transformer/get_request_transformer.dart
+++ b/packages/at_client/lib/src/transformer/request_transformer/get_request_transformer.dart
@@ -12,8 +12,6 @@ class GetRequestTransformer implements RequestTransformer<AtKey, VerbBuilder> {
 
   @override
   VerbBuilder transform(AtKey atKey, {RequestOptions? requestOptions}) {
-    // Set the default metadata if not already set.
-    atKey.metadata ??= Metadata();
     // Set sharedBy to currentAtSign if not set.
     atKey.sharedBy ??= _atClient.getCurrentAtSign();
     atKey.sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy);
diff --git a/packages/at_client/lib/src/transformer/request_transformer/notify_request_transformer.dart b/packages/at_client/lib/src/transformer/request_transformer/notify_request_transformer.dart
index 471bb29a5..2bbd454b7 100644
--- a/packages/at_client/lib/src/transformer/request_transformer/notify_request_transformer.dart
+++ b/packages/at_client/lib/src/transformer/request_transformer/notify_request_transformer.dart
@@ -21,8 +21,6 @@ class NotificationRequestTransformer
   @override
   Future<NotifyVerbBuilder> transform(
       NotificationParams notificationParams) async {
-    // If metadata is not set, initialize Metadata instance.
-    notificationParams.atKey.metadata ??= Metadata();
     // prepares notification builder
     NotifyVerbBuilder builder = await _prepareNotificationBuilder(
         notificationParams, atClientPreference);
@@ -43,8 +41,8 @@ class NotificationRequestTransformer
       AtClientPreference atClientPreference) async {
     var builder = NotifyVerbBuilder()
       ..id = notificationParams.id
-      ..sharedBy = notificationParams.atKey.sharedBy
-      ..sharedWith = notificationParams.atKey.sharedWith
+      ..atKey.sharedBy = notificationParams.atKey.sharedBy
+      ..atKey.sharedWith = notificationParams.atKey.sharedWith
       ..operation = notificationParams.operation
       ..messageType = notificationParams.messageType
       ..priority = notificationParams.priority
@@ -55,15 +53,15 @@ class NotificationRequestTransformer
     // Append namespace only to message type key. For message type text do not
     // append namespaces.
     if (notificationParams.messageType == MessageTypeEnum.key) {
-      builder.atKey = AtClientUtil.getKeyWithNameSpace(
+      builder.atKey.key = AtClientUtil.getKeyWithNameSpace(
           notificationParams.atKey, atClientPreference);
     }
     if (notificationParams.messageType == MessageTypeEnum.text) {
-      if (notificationParams.atKey.metadata!.isEncrypted!) {
-        builder.atKey = await _encryptNotificationValue(
-            notificationParams.atKey, notificationParams.atKey.key!);
+      if (notificationParams.atKey.metadata.isEncrypted) {
+        builder.atKey.key = await _encryptNotificationValue(
+            notificationParams.atKey, notificationParams.atKey.key);
       } else {
-        builder.atKey = notificationParams.atKey.key;
+        builder.atKey.key = notificationParams.atKey.key;
       }
     }
     return builder;
@@ -71,23 +69,26 @@ class NotificationRequestTransformer
 
   void _addMetadataToBuilder(
       NotifyVerbBuilder builder, NotificationParams notificationParams) {
-    builder.ttl = notificationParams.atKey.metadata?.ttl;
-    builder.ttb = notificationParams.atKey.metadata?.ttb;
-    builder.ttr = notificationParams.atKey.metadata?.ttr;
-    builder.ccd = notificationParams.atKey.metadata?.ccd;
-    builder.isPublic = notificationParams.atKey.metadata!.isPublic!;
-    if (notificationParams.atKey.metadata!.isEncrypted != null) {
-      builder.isTextMessageEncrypted =
-          notificationParams.atKey.metadata!.isEncrypted!;
-    }
-    builder.sharedKeyEncrypted =
-        notificationParams.atKey.metadata?.sharedKeyEnc;
-    builder.pubKeyChecksum = notificationParams.atKey.metadata?.pubKeyCS;
-    builder.encKeyName = notificationParams.atKey.metadata?.encKeyName;
-    builder.encAlgo = notificationParams.atKey.metadata?.encAlgo;
-    builder.ivNonce = notificationParams.atKey.metadata?.ivNonce;
-    builder.skeEncKeyName = notificationParams.atKey.metadata?.skeEncKeyName;
-    builder.skeEncAlgo = notificationParams.atKey.metadata?.skeEncAlgo;
+    builder.atKey.metadata.ttl = notificationParams.atKey.metadata.ttl;
+    builder.atKey.metadata.ttb = notificationParams.atKey.metadata.ttb;
+    builder.atKey.metadata.ttr = notificationParams.atKey.metadata.ttr;
+    builder.atKey.metadata.ccd = notificationParams.atKey.metadata.ccd;
+    builder.atKey.metadata.isPublic =
+        notificationParams.atKey.metadata.isPublic;
+    builder.atKey.metadata.isEncrypted =
+        notificationParams.atKey.metadata.isEncrypted;
+    builder.atKey.metadata.sharedKeyEnc =
+        notificationParams.atKey.metadata.sharedKeyEnc;
+    builder.atKey.metadata.pubKeyCS =
+        notificationParams.atKey.metadata.pubKeyCS;
+    builder.atKey.metadata.encKeyName =
+        notificationParams.atKey.metadata.encKeyName;
+    builder.atKey.metadata.encAlgo = notificationParams.atKey.metadata.encAlgo;
+    builder.atKey.metadata.ivNonce = notificationParams.atKey.metadata.ivNonce;
+    builder.atKey.metadata.skeEncKeyName =
+        notificationParams.atKey.metadata.skeEncKeyName;
+    builder.atKey.metadata.skeEncAlgo =
+        notificationParams.atKey.metadata.skeEncAlgo;
   }
 
   Future<String> _encryptNotificationValue(AtKey atKey, String value) async {
diff --git a/packages/at_client/lib/src/transformer/request_transformer/put_request_transformer.dart b/packages/at_client/lib/src/transformer/request_transformer/put_request_transformer.dart
index b3ad7cbe9..017103356 100644
--- a/packages/at_client/lib/src/transformer/request_transformer/put_request_transformer.dart
+++ b/packages/at_client/lib/src/transformer/request_transformer/put_request_transformer.dart
@@ -39,7 +39,7 @@ class PutRequestTransformer
     updateVerbBuilder.value = tuple.two;
 
     //Encrypt the data for non public keys
-    if (!atKey.metadata!.isPublic!) {
+    if (!atKey.metadata.isPublic) {
       var encryptionService = AtKeyEncryptionManager(_atClient)
           .get(atKey, _atClient.getCurrentAtSign()!);
       try {
@@ -52,13 +52,15 @@ class PutRequestTransformer
             ExceptionScenario.encryptionFailed, 'Failed to encrypt the data'));
         rethrow;
       }
-      updateVerbBuilder.sharedKeyEncrypted = atKey.metadata!.sharedKeyEnc;
-      updateVerbBuilder.pubKeyChecksum = atKey.metadata!.pubKeyCS;
-      updateVerbBuilder.encKeyName = atKey.metadata!.encKeyName;
-      updateVerbBuilder.encAlgo = atKey.metadata!.encAlgo;
-      updateVerbBuilder.ivNonce = atKey.metadata!.ivNonce;
-      updateVerbBuilder.skeEncKeyName = atKey.metadata!.skeEncKeyName;
-      updateVerbBuilder.skeEncAlgo = atKey.metadata!.skeEncAlgo;
+      updateVerbBuilder.atKey.metadata.sharedKeyEnc =
+          atKey.metadata.sharedKeyEnc;
+      updateVerbBuilder.atKey.metadata.pubKeyCS = atKey.metadata.pubKeyCS;
+      updateVerbBuilder.atKey.metadata.encKeyName = atKey.metadata.encKeyName;
+      updateVerbBuilder.atKey.metadata.encAlgo = atKey.metadata.encAlgo;
+      updateVerbBuilder.atKey.metadata.ivNonce = atKey.metadata.ivNonce;
+      updateVerbBuilder.atKey.metadata.skeEncKeyName =
+          atKey.metadata.skeEncKeyName;
+      updateVerbBuilder.atKey.metadata.skeEncAlgo = atKey.metadata.skeEncAlgo;
     } else {
       if (encryptionPrivateKey.isNull) {
         throw AtPrivateKeyNotFoundException('Failed to sign the public data');
@@ -66,12 +68,13 @@ class PutRequestTransformer
       final atSigningInput = AtSigningInput(updateVerbBuilder.value)
         ..signingMode = AtSigningMode.data;
       final signingResult = _atClient.atChops!.sign(atSigningInput);
-      updateVerbBuilder.dataSignature = signingResult.result;
+      updateVerbBuilder.atKey.metadata.dataSignature = signingResult.result;
       // Encode the public data if it contains new line characters
       if (updateVerbBuilder.value.contains('\n')) {
         updateVerbBuilder.value =
             AtEncoderImpl().encodeData(updateVerbBuilder.value, encodingType);
-        updateVerbBuilder.encoding = encodingType.toShortString();
+        updateVerbBuilder.atKey.metadata.encoding =
+            encodingType.toShortString();
       }
     }
 
@@ -82,31 +85,30 @@ class PutRequestTransformer
   UpdateVerbBuilder _populateUpdateVerbBuilder(
       AtKey atKey, AtClientPreference atClientPreference) {
     UpdateVerbBuilder updateVerbBuilder = UpdateVerbBuilder()
-      ..atKey = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
-      ..sharedWith = AtClientUtil.fixAtSign(atKey.sharedWith)
-      ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
-      ..isPublic =
-          (atKey.metadata?.isPublic != null) ? atKey.metadata!.isPublic! : false
-      ..isEncrypted = (atKey.metadata?.isEncrypted != null)
-          ? atKey.metadata?.isEncrypted!
-          : false
-      ..isBinary =
-          (atKey.metadata?.isBinary != null) ? atKey.metadata?.isBinary! : false
-      ..isLocal = atKey.isLocal;
+      ..atKey = (AtKey()
+        ..key = AtClientUtil.getKeyWithNameSpace(atKey, atClientPreference)
+        ..sharedWith = AtClientUtil.fixAtSign(atKey.sharedWith)
+        ..sharedBy = AtClientUtil.fixAtSign(atKey.sharedBy)
+        ..isLocal = atKey.isLocal
+        ..metadata = (Metadata()
+          ..isPublic = atKey.metadata.isPublic
+          ..isEncrypted = atKey.metadata.isEncrypted
+          ..isBinary = atKey.metadata.isBinary));
 
-    if (atKey.metadata!.ttl != null) {
-      updateVerbBuilder.ttl = atKey.metadata!.ttl;
+    if (atKey.metadata.ttl != null) {
+      updateVerbBuilder.atKey.metadata.ttl = atKey.metadata.ttl;
     }
-    if (atKey.metadata!.ttb != null) {
-      updateVerbBuilder.ttb = atKey.metadata!.ttb;
+    if (atKey.metadata.ttb != null) {
+      updateVerbBuilder.atKey.metadata.ttb = atKey.metadata.ttb;
     }
-    if (atKey.metadata!.ttr != null) {
-      updateVerbBuilder.ttr = atKey.metadata!.ttr;
+    if (atKey.metadata.ttr != null) {
+      updateVerbBuilder.atKey.metadata.ttr = atKey.metadata.ttr;
     }
-    if (atKey.metadata!.ccd != null) {
-      updateVerbBuilder.ccd = atKey.metadata!.ccd;
+    if (atKey.metadata.ccd != null) {
+      updateVerbBuilder.atKey.metadata.ccd = atKey.metadata.ccd;
     }
-    updateVerbBuilder.dataSignature = atKey.metadata!.dataSignature;
+    updateVerbBuilder.atKey.metadata.dataSignature =
+        atKey.metadata.dataSignature;
     return updateVerbBuilder;
   }
 }
diff --git a/packages/at_client/lib/src/transformer/response_transformer/get_response_transformer.dart b/packages/at_client/lib/src/transformer/response_transformer/get_response_transformer.dart
index 5e97175d8..517b6b09a 100644
--- a/packages/at_client/lib/src/transformer/response_transformer/get_response_transformer.dart
+++ b/packages/at_client/lib/src/transformer/response_transformer/get_response_transformer.dart
@@ -33,7 +33,7 @@ class GetResponseTransformer
           decodedResponse['metaData'], _isKeyPublic(decodedResponse['key']),
           isCached: decodedResponse['key'].startsWith('cached:'));
       atValue.metadata = metadata;
-      tuple.one.metadata = metadata;
+      tuple.one.metadata = metadata!;
     }
 
     // For public and cached public keys, data is not encrypted.
@@ -62,9 +62,7 @@ class GetResponseTransformer
     // After decrypting the data, if data is binary, decode the data
     // For cached keys, isBinary is not on server-side. Hence getting
     // isBinary from AtKey.
-    if (tuple.one.metadata != null &&
-        tuple.one.metadata!.isBinary != null &&
-        tuple.one.metadata!.isBinary!) {
+    if (tuple.one.metadata.isBinary) {
       atValue.value = Base2e15.decode(atValue.value);
     }
     return atValue;
diff --git a/packages/at_client/lib/src/transformer/response_transformer/notification_response_transformer.dart b/packages/at_client/lib/src/transformer/response_transformer/notification_response_transformer.dart
index 26474c46b..8d307789f 100644
--- a/packages/at_client/lib/src/transformer/response_transformer/notification_response_transformer.dart
+++ b/packages/at_client/lib/src/transformer/response_transformer/notification_response_transformer.dart
@@ -50,8 +50,10 @@ class NotificationResponseTransformer
     AtKey atKey = AtKey()
       ..key = key
       ..sharedWith = atNotification.to
-      ..sharedBy = atNotification.from
-      ..metadata = atNotification.metadata;
+      ..sharedBy = atNotification.from;
+    if (atNotification.metadata != null) {
+      atKey.metadata = atNotification.metadata!;
+    }
 
     if (atNotification.messageType.isNotNull &&
         atNotification.messageType!.toLowerCase().contains('text') &&
@@ -65,7 +67,7 @@ class NotificationResponseTransformer
         // The shared_key (which is a reserved key) has different decryption process
         // and is not a user created key.
         // Hence do not decrypt if key's are reserved keys
-        AtKey.getKeyType(atKey.key!) != KeyType.reservedKey) {
+        AtKey.getKeyType(atKey.toString()) != KeyType.reservedKey) {
       // decrypt the value
       atNotification.value =
           await _getDecryptedValue(atKey, atNotification.value!);
diff --git a/packages/at_client/lib/src/util/at_client_util.dart b/packages/at_client/lib/src/util/at_client_util.dart
index fddc7e076..60f585a2a 100644
--- a/packages/at_client/lib/src/util/at_client_util.dart
+++ b/packages/at_client/lib/src/util/at_client_util.dart
@@ -1,5 +1,4 @@
 import 'dart:convert';
-import 'dart:typed_data';
 
 import 'package:at_client/at_client.dart';
 import 'package:at_client/src/converters/encoder/at_encoder.dart';
@@ -34,8 +33,7 @@ class AtClientUtil {
   static String signChallenge(String challenge, String privateKey) {
     var key = RSAPrivateKey.fromString(privateKey);
     challenge = challenge.trim();
-    var signature =
-        key.createSHA256Signature(utf8.encode(challenge) as Uint8List);
+    var signature = key.createSHA256Signature(utf8.encode(challenge));
     return base64Encode(signature);
   }
 
@@ -85,8 +83,12 @@ class AtClientUtil {
     metadata.ttl = metadataMap[AtConstants.ttl];
     metadata.ttb = metadataMap[AtConstants.ttb];
     metadata.ccd = metadataMap[AtConstants.ccd];
-    metadata.isBinary = metadataMap[AtConstants.isBinary];
-    metadata.isEncrypted = metadataMap[AtConstants.isEncrypted];
+    metadata.isBinary = (metadataMap[AtConstants.isBinary] == null)
+        ? false
+        : metadataMap[AtConstants.isBinary];
+    metadata.isEncrypted = (metadataMap[AtConstants.isEncrypted] == null)
+        ? false
+        : metadataMap[AtConstants.isEncrypted];
     metadata.dataSignature = metadataMap[AtConstants.publicDataSignature];
     metadata.sharedKeyEnc = metadataMap[AtConstants.sharedKeyEncrypted];
     metadata.pubKeyCS = metadataMap[AtConstants.sharedWithPublicKeyCheckSum];
@@ -109,16 +111,14 @@ class AtClientUtil {
   /// else namespace is not appended
   static String getKeyWithNameSpace(
       AtKey atKey, AtClientPreference atClientPreference) {
-    // If metadata is null, initialize with new Metadata.
-    atKey.metadata ??= Metadata();
     // Do not append namespace for encryption keys.
-    if (!(atKey.metadata!.namespaceAware)) {
-      return atKey.key!;
+    if (!(atKey.metadata.namespaceAware)) {
+      return atKey.key;
     }
     //Do not append namespace if already appended
-    if (atKey.key?.substring(atKey.key!.lastIndexOf('.') + 1) ==
+    if (atKey.key.substring(atKey.key.lastIndexOf('.') + 1) ==
         atClientPreference.namespace) {
-      return atKey.key!;
+      return atKey.key;
     }
     // If key does not have any namespace, append the namespace to the key.
     if (atKey.namespace.isNotNull) {
@@ -127,7 +127,7 @@ class AtClientUtil {
     if (atClientPreference.namespace.isNotNull) {
       return '${atKey.key}.${atClientPreference.namespace}';
     }
-    return atKey.key!;
+    return atKey.key;
   }
 
   // TODO Remove this once AtUtils.fixAtSign accepts and returns String?
diff --git a/packages/at_client/lib/src/util/at_client_validation.dart b/packages/at_client/lib/src/util/at_client_validation.dart
index 9f814b3e1..81e95fc69 100644
--- a/packages/at_client/lib/src/util/at_client_validation.dart
+++ b/packages/at_client/lib/src/util/at_client_validation.dart
@@ -97,8 +97,8 @@ class AtClientValidation {
     }
     // If key starts with 'cached:' (or) if the metadata of key has isCached set to true; it represent
     // a cached key. Prevent client updating the cached key. Hence throw exception.
-    if (atKey.key!.startsWith('${AtConstants.cached}:') ||
-        (atKey.metadata != null && atKey.metadata!.isCached)) {
+    if (atKey.key.startsWith('${AtConstants.cached}:') ||
+        (atKey.metadata.isCached)) {
       throw AtKeyException('Cannot create/update a cached key');
     }
     // If namespace is not set on key and in preferences, throw exception
diff --git a/packages/at_client/lib/src/util/at_collection_utils.dart b/packages/at_client/lib/src/util/at_collection_utils.dart
index 3cdee5787..d4361e745 100644
--- a/packages/at_client/lib/src/util/at_collection_utils.dart
+++ b/packages/at_client/lib/src/util/at_collection_utils.dart
@@ -20,10 +20,10 @@ class AtCollectionUtil {
     return AtKey()
       ..key = key
       ..metadata = Metadata()
-      ..metadata!.ttr = -1
+      ..metadata.ttr = -1
       ..sharedWith = sharedWith
-      ..metadata!.ttl = ttl
-      ..metadata!.ttb = ttb
+      ..metadata.ttl = ttl
+      ..metadata.ttb = ttb
       ..sharedBy = _getAtClient().getCurrentAtSign();
   }
 }
diff --git a/packages/at_client/pubspec.yaml b/packages/at_client/pubspec.yaml
index 6b2d9bc2d..a278cf631 100644
--- a/packages/at_client/pubspec.yaml
+++ b/packages/at_client/pubspec.yaml
@@ -33,13 +33,30 @@ dependencies:
   at_base2e15: ^1.0.0
   at_commons: ^3.0.57
   at_utils: ^3.0.15
-  at_chops: ^1.0.5
+  at_chops: ^1.0.6
   at_lookup: ^3.0.41
   at_persistence_spec: ^2.0.14
   at_persistence_secondary_server: ^3.0.59
   meta: ^1.8.0
   version: ^3.0.2
 
+dependency_overrides:
+  at_persistence_secondary_server:
+    git:
+      url: https://github.com/atsign-foundation/at_server.git
+      path: packages/at_persistence_secondary_server
+      ref: uptake_commons_4.0.0
+  at_lookup:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_lookup
+      ref: uptake_commons_changes_into_lookup
+  at_commons:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_commons
+      ref: trunk
+
 dev_dependencies:
   lints: ^2.1.1
   test: ^1.21.4
diff --git a/packages/at_client/test/at_client_util_test.dart b/packages/at_client/test/at_client_util_test.dart
index fb03942e9..13bf1bb61 100644
--- a/packages/at_client/test/at_client_util_test.dart
+++ b/packages/at_client/test/at_client_util_test.dart
@@ -1,30 +1,33 @@
 import 'package:at_client/src/util/at_client_util.dart';
 import 'package:at_commons/at_builders.dart';
+import 'package:at_commons/at_commons.dart';
 import 'package:test/test.dart';
 
 void main() {
   group('A group of update builder tests', () {
     test('test non public key', () {
       var builder = UpdateVerbBuilder()
-        ..atKey = 'privatekey:at_pkam_privatekey';
+        ..atKey.key = 'privatekey:at_pkam_privatekey';
       var updateKey = builder.buildKey();
       expect(updateKey, 'privatekey:at_pkam_privatekey');
     });
 
     test('test public key', () {
       var builder = UpdateVerbBuilder()
-        ..isPublic = true
-        ..atKey = 'phone'
-        ..sharedBy = 'alice';
+        ..atKey = (AtKey()
+          ..key = 'phone'
+          ..sharedBy = 'alice'
+          ..metadata = (Metadata()..isPublic = true));
       var updateKey = builder.buildKey();
       expect(updateKey, 'public:phone@alice');
     });
 
     test('test key sharedwith another atsign', () {
       var builder = UpdateVerbBuilder()
-        ..sharedWith = 'bob'
-        ..atKey = 'phone'
-        ..sharedBy = 'alice';
+        ..atKey = (AtKey()
+          ..key = 'phone'
+          ..sharedWith = 'bob'
+          ..sharedBy = 'alice');
       var updateKey = builder.buildKey();
       expect(updateKey, '@bob:phone@alice');
     });
diff --git a/packages/at_client/test/decryption_service_test.dart b/packages/at_client/test/decryption_service_test.dart
index f0a1e1203..589bf0520 100644
--- a/packages/at_client/test/decryption_service_test.dart
+++ b/packages/at_client/test/decryption_service_test.dart
@@ -32,12 +32,14 @@ void main() {
   LocalSecondary mockLocalSecondary = MockLocalSecondary();
   var atClientPreferenceWithAtChops = AtClientPreference();
   var lookupVerbBuilder = LookupVerbBuilder()
-    ..atKey = 'phone.wavi'
-    ..sharedBy = '@alice';
+    ..atKey = (AtKey()
+      ..key = 'phone.wavi'
+      ..sharedBy = '@alice');
 
   var llookupVerbBuilder = LLookupVerbBuilder()
-    ..atKey = 'shared_key.sitaram'
-    ..sharedBy = '@murali';
+    ..atKey = (AtKey()
+      ..key = 'shared_key.sitaram'
+      ..sharedBy = '@murali');
 
   setUp(() {
     reset(mockAtLookup);
diff --git a/packages/at_client/test/encryption_service_test.dart b/packages/at_client/test/encryption_service_test.dart
index 85b2f228d..a98787e0f 100644
--- a/packages/at_client/test/encryption_service_test.dart
+++ b/packages/at_client/test/encryption_service_test.dart
@@ -102,12 +102,12 @@ void main() {
       var selfKeyEncryption = SelfKeyEncryption(mockAtClient);
 
       var atKey = AtKey.self('phone', namespace: 'wavi').build();
-      atKey.metadata!.ivNonce = EncryptionUtil.generateIV();
+      atKey.metadata.ivNonce = EncryptionUtil.generateIV();
 
       var encryptedData = await selfKeyEncryption.encrypt(atKey, value);
       var response = EncryptionUtil.decryptValue(
           encryptedData, selfEncryptionKey,
-          ivBase64: atKey.metadata!.ivNonce);
+          ivBase64: atKey.metadata.ivNonce);
       expect(response, value);
     });
   });
@@ -127,7 +127,7 @@ void main() {
             ..one = atKey
             ..two = value,
           encryptionPrivateKey: encryptionPrivateKey);
-      assert(updateVerbBuilder.dataSignature != null);
+      assert(updateVerbBuilder.atKey.metadata.dataSignature != null);
     });
   });
 
@@ -375,8 +375,8 @@ void main() {
           .thenAnswer((_) => (AtEncryptionResult()..result = sharedKey));
 
       var encryptedValue = await sharedKeyEncryption.encrypt(atKey, value);
-      expect(atKey.metadata?.sharedKeyEnc.isNotNull, true);
-      expect(atKey.metadata?.pubKeyCS.isNotNull, true);
+      expect(atKey.metadata.sharedKeyEnc.isNotNull, true);
+      expect(atKey.metadata.pubKeyCS.isNotNull, true);
 
       var decryptedSharedKey =
           // ignore: deprecated_member_use_from_same_package
@@ -398,7 +398,7 @@ void main() {
       var atKey = (AtKey.shared('phone', namespace: 'wavi', sharedBy: '@alice')
             ..sharedWith('@bob'))
           .build();
-      atKey.metadata!.ivNonce = EncryptionUtil.generateIV();
+      atKey.metadata.ivNonce = EncryptionUtil.generateIV();
       var value = 'hello';
 
       when(() => mockLocalSecondary
@@ -418,10 +418,10 @@ void main() {
       expect(decryptedSharedKey, sharedKey);
       var decryptedValue = EncryptionUtil.decryptValue(
           encryptedValue, decryptedSharedKey,
-          ivBase64: atKey.metadata!.ivNonce);
+          ivBase64: atKey.metadata.ivNonce);
       expect(decryptedValue, value);
-      expect(atKey.metadata?.sharedKeyEnc.isNotNull, true);
-      expect(atKey.metadata?.pubKeyCS.isNotNull, true);
+      expect(atKey.metadata.sharedKeyEnc.isNotNull, true);
+      expect(atKey.metadata.pubKeyCS.isNotNull, true);
     });
 
     test('test to verify legacy encryption when a new shared key is generated',
@@ -466,8 +466,8 @@ void main() {
               encryptedValue, sharedKeyEncryption.sharedKey,
               ivBase64: null),
           originalValue);
-      expect(atKey.metadata?.sharedKeyEnc.isNotNull, true);
-      expect(atKey.metadata?.pubKeyCS.isNotNull, true);
+      expect(atKey.metadata.sharedKeyEnc.isNotNull, true);
+      expect(atKey.metadata.pubKeyCS.isNotNull, true);
     });
 
     test('test to verify encryption when a new shared key is generated',
@@ -497,7 +497,7 @@ void main() {
       var atKey = (AtKey.shared('phone', namespace: 'wavi', sharedBy: '@alice')
             ..sharedWith('@bob'))
           .build();
-      atKey.metadata!.ivNonce = EncryptionUtil.generateIV();
+      atKey.metadata.ivNonce = EncryptionUtil.generateIV();
       var originalValue = 'hello';
 
       var encryptedValue =
@@ -505,10 +505,10 @@ void main() {
       expect(
           EncryptionUtil.decryptValue(
               encryptedValue, sharedKeyEncryption.sharedKey,
-              ivBase64: atKey.metadata!.ivNonce),
+              ivBase64: atKey.metadata.ivNonce),
           originalValue);
-      expect(atKey.metadata?.sharedKeyEnc.isNotNull, true);
-      expect(atKey.metadata?.pubKeyCS.isNotNull, true);
+      expect(atKey.metadata.sharedKeyEnc.isNotNull, true);
+      expect(atKey.metadata.pubKeyCS.isNotNull, true);
     });
 
     test(
@@ -569,7 +569,7 @@ class LLookupEncryptedSharedKeyMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is LLookupVerbBuilder && item.atKey!.contains('shared_key')) {
+    if (item is LLookupVerbBuilder && item.atKey.key.contains('shared_key')) {
       return true;
     }
     return false;
@@ -583,7 +583,7 @@ class EncryptionPublicKeyMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is LLookupVerbBuilder && item.atKey!.contains('publickey')) {
+    if (item is LLookupVerbBuilder && item.atKey.key.contains('publickey')) {
       return true;
     }
     return false;
@@ -597,7 +597,7 @@ class UpdateEncryptedSharedKeyMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is UpdateVerbBuilder && item.atKey!.contains('shared_key')) {
+    if (item is UpdateVerbBuilder && item.atKey.key.contains('shared_key')) {
       return true;
     }
     return false;
diff --git a/packages/at_client/test/full_stack_test.dart b/packages/at_client/test/full_stack_test.dart
index 704b7d0fe..7a8997078 100644
--- a/packages/at_client/test/full_stack_test.dart
+++ b/packages/at_client/test/full_stack_test.dart
@@ -62,8 +62,9 @@ void main() {
     var myEncryptedBobSharedKey = EncryptionUtil.encryptKey(
         bobSharedKey, alicesRSAKeyPair.publicKey.toString());
     var llookupMySharedKeyForBob = LLookupVerbBuilder()
-      ..atKey = '${AtConstants.atEncryptionSharedKey}.bob'
-      ..sharedBy = '@alice';
+      ..atKey = (AtKey()
+        ..key = '${AtConstants.atEncryptionSharedKey}.bob'
+        ..sharedBy = '@alice');
 
     var victorSymKey = EncryptionUtil.generateAESKey();
     var myEncryptedVicSymKey = EncryptionUtil.encryptKey(
@@ -137,7 +138,8 @@ void main() {
           throw SecondaryConnectException(
               'Mock remote atServer is unavailable');
         }
-        var val = remotePLookupMap['${builder.atKey}${builder.sharedBy}'];
+        var val =
+            remotePLookupMap['${builder.atKey.key}${builder.atKey.sharedBy}'];
         if (val != null) {
           return val;
         } else {
@@ -159,7 +161,7 @@ void main() {
           throw SecondaryConnectException(
               'Mock remote atServer is unavailable');
         }
-        var val = remoteLLookupMap[builder.atKeyObj.toString()];
+        var val = remoteLLookupMap[builder.atKey.toString()];
         if (val != null) {
           return val;
         } else {
@@ -182,7 +184,7 @@ void main() {
           throw SecondaryConnectException(
               'Mock remote atServer is unavailable');
         }
-        remoteUpdatedMap[builder.atKeyObj.toString()] = builder.value;
+        remoteUpdatedMap[builder.atKey.toString()] = builder.value;
         return 'data:${remoteCommitId++}';
       });
 
@@ -199,7 +201,7 @@ void main() {
           throw SecondaryConnectException(
               'Mock remote atServer is unavailable');
         }
-        remoteDeletedSet.add(builder.atKeyObj.toString());
+        remoteDeletedSet.add(builder.atKey.toString());
         return 'data:${remoteCommitId++}';
       });
     });
@@ -210,7 +212,7 @@ void main() {
 
         var atKey = AtKey.self('test_put').build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNull);
+        expect(atKey.metadata.ivNonce, isNull);
 
         var atData = await (atClient
             .getLocalSecondary()!
@@ -229,7 +231,7 @@ void main() {
 
         var atKey = AtKey.self('test_put').build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNull);
+        expect(atKey.metadata.ivNonce, isNull);
 
         var atData = await (atClient
             .getLocalSecondary()!
@@ -249,7 +251,7 @@ void main() {
 
         var atKey = AtKey.self('test_put').build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNotNull);
+        expect(atKey.metadata.ivNonce, isNotNull);
 
         var atData = await (atClient
             .getLocalSecondary()!
@@ -265,7 +267,7 @@ void main() {
             false);
         expect(
             EncryptionUtil.decryptValue(cipherText, selfEncryptionKey,
-                ivBase64: atKey.metadata?.ivNonce),
+                ivBase64: atKey.metadata.ivNonce),
             clearText);
 
         var getResult = await atClient.get(atKey);
@@ -277,7 +279,7 @@ void main() {
 
         var atKey = AtKey.self('test_put').build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNotNull);
+        expect(atKey.metadata.ivNonce, isNotNull);
 
         fullStackPrefs.atProtocolEmitted = Version(1, 5, 0);
 
@@ -295,7 +297,7 @@ void main() {
             false);
         expect(
             EncryptionUtil.decryptValue(cipherText, selfEncryptionKey,
-                ivBase64: atKey.metadata?.ivNonce),
+                ivBase64: atKey.metadata.ivNonce),
             clearText);
 
         var getResult = await atClient.get(atKey);
@@ -309,7 +311,7 @@ void main() {
 
         var atKey = (AtKey.shared('test_put')..sharedWith('@bob')).build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNull);
+        expect(atKey.metadata.ivNonce, isNull);
 
         var atData = await (atClient
             .getLocalSecondary()!
@@ -328,7 +330,7 @@ void main() {
 
         var atKey = (AtKey.shared('test_put')..sharedWith('@bob')).build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNull);
+        expect(atKey.metadata.ivNonce, isNull);
 
         fullStackPrefs.atProtocolEmitted = Version(1, 5, 0);
         var atData = await (atClient
@@ -348,7 +350,7 @@ void main() {
 
         var atKey = (AtKey.shared('test_put')..sharedWith('@bob')).build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNotNull);
+        expect(atKey.metadata.ivNonce, isNotNull);
 
         var atData = await (atClient
             .getLocalSecondary()!
@@ -366,7 +368,7 @@ void main() {
             wrappedDecryptSucceeds(
                 cipherText: cipherText,
                 aesKey: selfEncryptionKey,
-                ivBase64: atKey.metadata?.ivNonce,
+                ivBase64: atKey.metadata.ivNonce,
                 clearText: clearText),
             false);
         expect(
@@ -378,7 +380,7 @@ void main() {
             false);
         expect(
             EncryptionUtil.decryptValue(cipherText, bobSharedKey,
-                ivBase64: atKey.metadata?.ivNonce),
+                ivBase64: atKey.metadata.ivNonce),
             clearText);
 
         var getResult = await atClient.get(atKey);
@@ -390,7 +392,7 @@ void main() {
 
         var atKey = (AtKey.shared('test_put')..sharedWith('@bob')).build();
         await atClient.put(atKey, clearText);
-        expect(atKey.metadata?.ivNonce, isNotNull);
+        expect(atKey.metadata.ivNonce, isNotNull);
 
         fullStackPrefs.atProtocolEmitted = Version(1, 5, 0);
         var atData = await (atClient
@@ -409,7 +411,7 @@ void main() {
             wrappedDecryptSucceeds(
                 cipherText: cipherText,
                 aesKey: selfEncryptionKey,
-                ivBase64: atKey.metadata?.ivNonce,
+                ivBase64: atKey.metadata.ivNonce,
                 clearText: clearText),
             false);
         expect(
@@ -421,7 +423,7 @@ void main() {
             false);
         expect(
             EncryptionUtil.decryptValue(cipherText, bobSharedKey,
-                ivBase64: atKey.metadata?.ivNonce),
+                ivBase64: atKey.metadata.ivNonce),
             clearText);
 
         var getResult = await atClient.get(atKey);
@@ -441,12 +443,12 @@ void main() {
             any(that: isA<UpdateVerbBuilder>()),
             sync: true)).thenAnswer((invocation) async {
           var builder = invocation.positionalArguments[0] as UpdateVerbBuilder;
-          if (builder.atKeyObj.toString() == atKey.toString()) {
+          if (builder.atKey.toString() == atKey.toString()) {
             print(
-                'mockRemoteSecondary.executeVerb with UpdateVerbBuilder for ${builder.atKeyObj.toString()} as expected');
+                'mockRemoteSecondary.executeVerb with UpdateVerbBuilder for ${builder.atKey.toString()} as expected');
             executedRemotely = true;
             return 'data:10';
-          } else if (builder.atKeyObj.toString() != '@bob:shared_key@alice') {
+          } else if (builder.atKey.toString() != '@bob:shared_key@alice') {
             print(builder.buildCommand());
             throw Exception(
                 'mockRemoteSecondary.executeVerb called with unexpected UpdateVerbBuilder');
@@ -487,7 +489,7 @@ void main() {
           print('DeleteVerbBuilder: ${builder.buildCommand()}');
           if (builder.buildKey() == atKey.toString()) {
             print(
-                'mockRemoteSecondary.executeVerb with DeleteVerbBuilder for ${builder.atKeyObj.toString()} as expected');
+                'mockRemoteSecondary.executeVerb with DeleteVerbBuilder for ${builder.atKey.toString()} as expected');
             executedRemotely = true;
             return 'data:10';
           } else {
diff --git a/packages/at_client/test/local_secondary_test.dart b/packages/at_client/test/local_secondary_test.dart
index 794913bdd..0007ca78f 100644
--- a/packages/at_client/test/local_secondary_test.dart
+++ b/packages/at_client/test/local_secondary_test.dart
@@ -35,6 +35,7 @@ class MockSecondaryKeyStore extends Mock implements SecondaryKeyStore {
     waviOtherNonHiddenKey,
     otherWaviOtherNonHiddenKey
   ];
+
   @override
   List<String> getKeys({String? regex}) {
     if (regex != null) {
@@ -151,10 +152,11 @@ void main() {
           atClientManager: atClientManager);
       final localSecondary = LocalSecondary(atClient);
       final verbBuilder = UpdateVerbBuilder()
-        ..isPublic = true
-        ..value = 'alice@gmail.com'
-        ..atKey = 'email'
-        ..sharedBy = atSign;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true))
+        ..value = 'alice@gmail.com';
       final executeResult =
           await localSecondary.executeVerb(verbBuilder, sync: false);
       expect(executeResult, isNotNull);
@@ -170,15 +172,17 @@ void main() {
           atClientManager: atClientManager);
       final localSecondary = LocalSecondary(atClient);
       final verbBuilder = UpdateVerbBuilder()
-        ..isPublic = true
-        ..value = 'alice@gmail.com'
-        ..atKey = 'email'
-        ..sharedBy = atSign;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true))
+        ..value = 'alice@gmail.com';
       await localSecondary.executeVerb(verbBuilder, sync: false);
       final llookupVerbBuilder = LLookupVerbBuilder()
-        ..atKey = 'email'
-        ..sharedBy = atSign
-        ..isPublic = true;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true));
       final llookupResult =
           await localSecondary.executeVerb(llookupVerbBuilder, sync: false);
       expect(llookupResult, 'data:alice@gmail.com');
@@ -193,20 +197,23 @@ void main() {
           atClientManager: atClientManager);
       final localSecondary = LocalSecondary(atClient);
       final verbBuilder = UpdateVerbBuilder()
-        ..isPublic = true
-        ..value = 'alice@gmail.com'
-        ..atKey = 'email'
-        ..sharedBy = atSign;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true))
+        ..value = 'alice@gmail.com';
       await localSecondary.executeVerb(verbBuilder, sync: false);
       final deleteVerbBuilder = DeleteVerbBuilder()
-        ..atKey = 'email'
-        ..sharedBy = atSign
-        ..isPublic = true;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true));
       await localSecondary.executeVerb(deleteVerbBuilder, sync: false);
       final llookupVerbBuilder = LLookupVerbBuilder()
-        ..atKey = 'email'
-        ..sharedBy = atSign
-        ..isPublic = true;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true));
       expect(localSecondary.executeVerb(llookupVerbBuilder, sync: false),
           throwsA(isA<KeyNotFoundException>()));
     });
@@ -220,15 +227,17 @@ void main() {
           atClientManager: atClientManager);
       final localSecondary = LocalSecondary(atClient);
       final verbBuilder_1 = UpdateVerbBuilder()
-        ..isPublic = true
-        ..value = 'alice@gmail.com'
-        ..atKey = 'email'
-        ..sharedBy = atSign;
+        ..atKey = (AtKey()
+          ..key = 'email'
+          ..sharedBy = atSign
+          ..metadata = (Metadata()..isPublic = true))
+        ..value = 'alice@gmail.com';
       await localSecondary.executeVerb(verbBuilder_1, sync: false);
       final verbBuilder_2 = UpdateVerbBuilder()
-        ..value = '+101-202-303'
-        ..atKey = 'phone'
-        ..sharedBy = atSign;
+        ..atKey = (AtKey()
+          ..key = 'phone'
+          ..sharedBy = atSign)
+        ..value = '+101-202-303';
       await localSecondary.executeVerb(verbBuilder_2, sync: false);
       final scanVerbBuilder = ScanVerbBuilder();
       final scanResult =
diff --git a/packages/at_client/test/notification_service_test.dart b/packages/at_client/test/notification_service_test.dart
index bf5dfd7ee..fb3f570c3 100644
--- a/packages/at_client/test/notification_service_test.dart
+++ b/packages/at_client/test/notification_service_test.dart
@@ -65,8 +65,8 @@ class MockSharedKeyEncryptionImpl extends Mock implements SharedKeyEncryption {
     //Set encryptionMetadata to atKey metadata
     atKey.metadata = Metadata();
     if (storeSharedKeyEncryptedWithData) {
-      atKey.metadata!.sharedKeyEnc = 'sharedKeyEnc';
-      atKey.metadata!.pubKeyCS = 'publicKeyCS';
+      atKey.metadata.sharedKeyEnc = 'sharedKeyEnc';
+      atKey.metadata.pubKeyCS = 'publicKeyCS';
     }
     return 'encryptedValue';
   }
@@ -119,8 +119,8 @@ void main() {
               AtClientPreference()..namespace = 'wavi',
               SharedKeyEncryption(mockAtClientImpl))
           .transform(notificationParams);
-      expect(notifyVerbBuilder.atKey, 'phone.wavi');
-      expect(notifyVerbBuilder.sharedWith, '@bob');
+      expect(notifyVerbBuilder.atKey.key, 'phone.wavi');
+      expect(notifyVerbBuilder.atKey.sharedWith, '@bob');
       expect(notifyVerbBuilder.messageType, MessageTypeEnum.key);
       expect(notifyVerbBuilder.priority, PriorityEnum.low);
       expect(notifyVerbBuilder.strategy, StrategyEnum.all);
@@ -145,14 +145,14 @@ void main() {
               AtClientPreference()..namespace = 'wavi',
               mockSharedKeyEncryptionImpl)
           .transform(notificationParams);
-      expect(notifyVerbBuilder.atKey, 'phone.wavi');
-      expect(notifyVerbBuilder.sharedWith, '@bob');
+      expect(notifyVerbBuilder.atKey.key, 'phone.wavi');
+      expect(notifyVerbBuilder.atKey.sharedWith, '@bob');
       expect(notifyVerbBuilder.messageType, MessageTypeEnum.key);
       expect(notifyVerbBuilder.priority, PriorityEnum.high);
       expect(notifyVerbBuilder.strategy, StrategyEnum.latest);
       expect(notifyVerbBuilder.value, 'encryptedValue');
-      expect(notifyVerbBuilder.sharedKeyEncrypted, 'sharedKeyEnc');
-      expect(notifyVerbBuilder.pubKeyChecksum, 'publicKeyCS');
+      expect(notifyVerbBuilder.atKey.metadata.sharedKeyEnc, 'sharedKeyEnc');
+      expect(notifyVerbBuilder.atKey.metadata.pubKeyCS, 'publicKeyCS');
       expect(notifyVerbBuilder.notifier, 'test-notifier');
       expect(notifyVerbBuilder.latestN, 2);
       expect(notifyVerbBuilder.ttln, Duration(minutes: 1).inMilliseconds);
@@ -169,8 +169,8 @@ void main() {
               mockSharedKeyEncryptionImpl)
           .transform(notificationParams);
       //upper case should be preserved in forText notifications
-      expect(notifyVerbBuilder.atKey, 'Hi How are you');
-      expect(notifyVerbBuilder.sharedWith, '@bob');
+      expect(notifyVerbBuilder.atKey.key, 'Hi How are you');
+      expect(notifyVerbBuilder.atKey.sharedWith, '@bob');
       expect(notifyVerbBuilder.messageType, MessageTypeEnum.text);
       expect(notifyVerbBuilder.priority, PriorityEnum.low);
       expect(notifyVerbBuilder.strategy, StrategyEnum.all);
@@ -187,8 +187,8 @@ void main() {
               AtClientPreference()..namespace = 'wavi',
               mockSharedKeyEncryptionImpl)
           .transform(notificationParams);
-      expect(notifyVerbBuilder.atKey, 'encryptedValue');
-      expect(notifyVerbBuilder.sharedWith, '@bob');
+      expect(notifyVerbBuilder.atKey.key, 'encryptedValue');
+      expect(notifyVerbBuilder.atKey.sharedWith, '@bob');
       expect(notifyVerbBuilder.messageType, MessageTypeEnum.text);
       expect(notifyVerbBuilder.priority, PriorityEnum.low);
       expect(notifyVerbBuilder.strategy, StrategyEnum.all);
@@ -486,7 +486,7 @@ void main() {
       NotificationParams notificationParams =
           NotificationParams.forUpdate(atKey, value: value);
       NotifyVerbBuilder notifyVerbBuilder = NotifyVerbBuilder()
-        ..atKey = atKey.toString()
+        ..atKey = atKey
         ..messageType = MessageTypeEnum.key
         ..value = 'demo-value';
 
@@ -509,7 +509,7 @@ void main() {
       NotificationParams notificationParams =
           NotificationParams.forText('Hello bob', '@bob');
       NotifyVerbBuilder notifyVerbBuilder = NotifyVerbBuilder()
-        ..atKey = '@bob:Hello bob';
+        ..atKey.key = '@bob:Hello bob';
 
       expect(
           () => notificationServiceImpl.notificationValueValidation(
@@ -1117,7 +1117,7 @@ class StatsAtKeyMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is AtKey && item.key!.contains('_latestNotificationIdv2')) {
+    if (item is AtKey && item.key.contains('_latestNotificationIdv2')) {
       return true;
     }
     return false;
diff --git a/packages/at_client/test/put_request_test.dart b/packages/at_client/test/put_request_test.dart
index c80bafc93..22425e73b 100644
--- a/packages/at_client/test/put_request_test.dart
+++ b/packages/at_client/test/put_request_test.dart
@@ -62,10 +62,12 @@ void main() {
             .transform(tuple, encryptionPrivateKey: encryptionPrivateKey);
         expect(updateVerbBuilder.value.contains('\n'),
             expectedResults['isNewLineCharPresentInOutput']);
-        expect(updateVerbBuilder.encoding, expectedResults['encoding']);
-        expect(updateVerbBuilder.dataSignature.isNotNull,
+        expect(updateVerbBuilder.atKey.metadata.encoding,
+            expectedResults['encoding']);
+        expect(updateVerbBuilder.atKey.metadata.dataSignature.isNotNull,
             expectedResults['isDataSignaturePresent']);
-        final dataSignatureWithoutAtChops = updateVerbBuilder.dataSignature;
+        final dataSignatureWithoutAtChops =
+            updateVerbBuilder.atKey.metadata.dataSignature;
         when(() => mockAtClient.getPreferences())
             .thenAnswer((_) => atClientPreferenceWithAtChops);
 
@@ -75,10 +77,12 @@ void main() {
             encryptionPrivateKey: encryptionPrivateKey);
         expect(updateVerbBuilder.value.contains('\n'),
             expectedResults['isNewLineCharPresentInOutput']);
-        expect(updateVerbBuilder.encoding, expectedResults['encoding']);
-        expect(updateVerbBuilder.dataSignature.isNotNull,
+        expect(updateVerbBuilder.atKey.metadata.encoding,
+            expectedResults['encoding']);
+        expect(updateVerbBuilder.atKey.metadata.dataSignature.isNotNull,
             expectedResults['isDataSignaturePresent']);
-        expect(updateVerbBuilder.dataSignature, dataSignatureWithoutAtChops);
+        expect(updateVerbBuilder.atKey.metadata.dataSignature,
+            dataSignatureWithoutAtChops);
       });
     });
   });
diff --git a/packages/at_client/test/remote_secondary_test.dart b/packages/at_client/test/remote_secondary_test.dart
index d83a0ed7e..050e40594 100644
--- a/packages/at_client/test/remote_secondary_test.dart
+++ b/packages/at_client/test/remote_secondary_test.dart
@@ -64,8 +64,9 @@ void main() {
     test('executeAndParse using llookup', () async {
       String fakeLookupData = 'data:lookup data stub';
       LookupVerbBuilder lookupVerbBuilder = LookupVerbBuilder()
-        ..atKey = 'dummy_key'
-        ..sharedBy = '@alice';
+        ..atKey = (AtKey()
+          ..key = 'dummy_key'
+          ..sharedBy = '@alice');
       when(() => mockAtLookUp.executeVerb(lookupVerbBuilder))
           .thenAnswer((_) async => fakeLookupData);
       RemoteSecondary remoteSecondary =
diff --git a/packages/at_client/test/sync_new_test.dart b/packages/at_client/test/sync_new_test.dart
index 26e11746d..1a816fb38 100644
--- a/packages/at_client/test/sync_new_test.dart
+++ b/packages/at_client/test/sync_new_test.dart
@@ -787,10 +787,8 @@ void main() {
       var atData = AtData();
       atData.data = encryptionPrivateKey;
       //------------Operation---------------------------------
-      String atKey = (AtKey.self(AtConstants.atEncryptionPrivateKey,
-              sharedBy: TestResources.atsign))
-          .build()
-          .toString();
+      String atKey =
+          (AtKey.self(AtConstants.atEncryptionPrivateKey)).build().toString();
       int putCommitId = await keystore!.put(atKey, atData);
       // -----------Assertions---------------------------------
       // verifying the key in the key store
@@ -829,10 +827,8 @@ void main() {
       var atData = AtData();
       atData.data = pkamPrivateKey;
       //------------Operation---------------------------------
-      String atKey = (AtKey.self(AtConstants.atPkamPrivateKey,
-              sharedBy: TestResources.atsign))
-          .build()
-          .toString();
+      String atKey =
+          (AtKey.self(AtConstants.atPkamPrivateKey)).build().toString();
       int putCommitId = await keystore!.put(atKey, atData);
       // -----------Assertions---------------------------------
       // verifying the key in the key store
@@ -2076,22 +2072,25 @@ void main() {
 
       // Create uncommitted entries in local storage
       await localSecondary.executeVerb(UpdateVerbBuilder()
-        ..atKey = 'firstKey'
-        ..sharedBy = TestResources.atsign
-        ..sharedWith = '@bob'
+        ..atKey = (AtKey()
+          ..key = 'firstKey'
+          ..sharedBy = TestResources.atsign
+          ..sharedWith = '@bob')
         ..value = 'value1');
 
       UpdateVerbBuilder updateBuilderForSecondKey = UpdateVerbBuilder()
-        ..atKey = 'secondKey'
-        ..sharedBy = TestResources.atsign
-        ..sharedWith = '@bob'
+        ..atKey = (AtKey()
+          ..key = 'secondKey'
+          ..sharedBy = TestResources.atsign
+          ..sharedWith = '@bob')
         ..value = 'value1';
       await localSecondary.executeVerb(updateBuilderForSecondKey);
 
       DeleteVerbBuilder deleteBuilderForThirdKey = DeleteVerbBuilder()
-        ..atKey = 'firstKey'
-        ..sharedBy = TestResources.atsign
-        ..sharedWith = '@bob';
+        ..atKey = (AtKey()
+          ..key = 'firstKey'
+          ..sharedBy = TestResources.atsign
+          ..sharedWith = '@bob');
       await localSecondary.executeVerb(deleteBuilderForThirdKey);
 
       // Mock Responses
@@ -3012,9 +3011,10 @@ void main() {
               throw KeyNotFoundException('key is not found in keystore'));
 
       await localSecondary.executeVerb(DeleteVerbBuilder()
-        ..sharedWith = '@alice'
-        ..atKey = 'conflict-key'
-        ..sharedBy = TestResources.atsign);
+        ..atKey = (AtKey()
+          ..key = 'conflict-key'
+          ..sharedWith = '@alice'
+          ..sharedBy = TestResources.atsign));
       CustomSyncProgressListener progressListener =
           CustomSyncProgressListener();
       syncService.addProgressListener(progressListener);
@@ -4400,7 +4400,7 @@ class LastReceivedServerCommitIdMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is AtKey && item.key!.startsWith('lastreceivedservercommitid')) {
+    if (item is AtKey && item.key.startsWith('lastreceivedservercommitid')) {
       return true;
     }
     return false;
@@ -4415,7 +4415,7 @@ class ConflictKeyMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is AtKey && item.key!.contains('conflict')) {
+    if (item is AtKey && item.key.contains('conflict')) {
       return true;
     }
     return false;
diff --git a/packages/at_client/test/sync_service_test.dart b/packages/at_client/test/sync_service_test.dart
index c9b761e34..3bdec2daf 100644
--- a/packages/at_client/test/sync_service_test.dart
+++ b/packages/at_client/test/sync_service_test.dart
@@ -321,7 +321,7 @@ class LastReceivedServerCommitIdMatcher extends Matcher {
 
   @override
   bool matches(item, Map matchState) {
-    if (item is AtKey && item.key!.startsWith('lastreceivedservercommitid')) {
+    if (item is AtKey && item.key.startsWith('lastreceivedservercommitid')) {
       return true;
     }
     return false;
diff --git a/packages/at_client_mobile/lib/src/at_client_auth.dart b/packages/at_client_mobile/lib/src/at_client_auth.dart
index a2308b767..1469dbff1 100644
--- a/packages/at_client_mobile/lib/src/at_client_auth.dart
+++ b/packages/at_client_mobile/lib/src/at_client_auth.dart
@@ -68,7 +68,8 @@ class AtClientAuthenticator implements AtClientAuth {
         }
         // send public key to remote Secondary server
         logger.finer('updating pkam public key to server');
-        var updateCommand = 'update:$AT_PKAM_PUBLIC_KEY $publicKey\n';
+        var updateCommand =
+            'update:${AtConstants.atPkamPublicKey} $publicKey\n';
         // auth is false since already cram authenticated
         var pkamUpdateResult = await atLookupInitialAuth
             .executeCommand(updateCommand, auth: false);
@@ -103,7 +104,8 @@ class AtClientAuthenticator implements AtClientAuth {
           );
           await _keyChainManager.storeAtSign(atSign: atSignItem);
         }
-        var deleteBuilder = DeleteVerbBuilder()..atKey = AT_CRAM_SECRET;
+        var deleteBuilder = DeleteVerbBuilder()
+          ..atKey = (AtKey()..key = AtConstants.atCramSecret);
         var deleteResponse =
             await atLookupInitialAuth.executeVerb(deleteBuilder);
         logger.finer('cram secret delete response : $deleteResponse');
diff --git a/packages/at_client_mobile/lib/src/at_client_service.dart b/packages/at_client_mobile/lib/src/at_client_service.dart
index a8286cc1e..eb394c722 100644
--- a/packages/at_client_mobile/lib/src/at_client_service.dart
+++ b/packages/at_client_mobile/lib/src/at_client_service.dart
@@ -122,22 +122,24 @@ class AtClientService {
     //Store keys into local secondary.
     await _atClient!
         .getLocalSecondary()!
-        .putValue(AT_PKAM_PUBLIC_KEY, pkamPublicKey);
+        .putValue(AtConstants.atPkamPublicKey, pkamPublicKey);
 
     await _atClient!
         .getLocalSecondary()!
-        .putValue(AT_PKAM_PRIVATE_KEY, pkamPrivateKey);
+        .putValue(AtConstants.atPkamPrivateKey, pkamPrivateKey);
 
     await _atClient!
         .getLocalSecondary()!
-        .putValue(AT_ENCRYPTION_PRIVATE_KEY, encryptPrivateKey);
+        .putValue(AtConstants.atEncryptionPrivateKey, encryptPrivateKey);
 
     var updateBuilder = UpdateVerbBuilder()
-      ..atKey = 'publickey'
-      ..isPublic = true
-      ..sharedBy = atSign
-      ..value = encryptPublicKey
-      ..metadata.ttr = -1;
+      ..atKey = (AtKey()
+        ..key = 'publickey'
+        ..sharedBy = atSign
+        ..metadata = (Metadata()
+          ..ttr = -1
+          ..isPublic = true))
+      ..value = encryptPublicKey;
 
     await _atClient!
         .getLocalSecondary()!
@@ -145,7 +147,7 @@ class AtClientService {
 
     await _atClient!
         .getLocalSecondary()!
-        .putValue(AT_ENCRYPTION_SELF_KEY, selfEncryptionKey);
+        .putValue(AtConstants.atEncryptionSelfKey, selfEncryptionKey);
 
     // Verify if keys are added to local storage.
     var result = await _getKeysFromLocalSecondary(atSign);
diff --git a/packages/at_client_mobile/pubspec.yaml b/packages/at_client_mobile/pubspec.yaml
index b65c11156..905bbc127 100644
--- a/packages/at_client_mobile/pubspec.yaml
+++ b/packages/at_client_mobile/pubspec.yaml
@@ -22,6 +22,29 @@ dependencies:
   at_lookup: ^3.0.38
   at_client: ^3.0.64
 
+dependency_overrides:
+  at_commons:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_commons
+      ref: trunk
+  at_persistence_secondary_server:
+    git:
+      url: https://github.com/atsign-foundation/at_server.git
+      path: packages/at_persistence_secondary_server
+      ref: uptake_commons_4.0.0
+  at_lookup:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_lookup
+      ref: uptake_commons_changes_into_lookup
+  at_client:
+    git:
+      url: https://github.com/atsign-foundation/at_client_sdk.git
+      path: packages/at_client
+      ref: uptake_commons_4.0.0
+
+
 dev_dependencies:
   lints: ^2.0.0
   test: ^1.6.0
diff --git a/packages/at_client_mobile/test/at_client_service_test.dart b/packages/at_client_mobile/test/at_client_service_test.dart
index de1fcba8f..7f7fc58e2 100644
--- a/packages/at_client_mobile/test/at_client_service_test.dart
+++ b/packages/at_client_mobile/test/at_client_service_test.dart
@@ -303,8 +303,8 @@ void main() {
           sync: true)).thenAnswer((invocation) async {
         var verbBuilder = invocation.positionalArguments[0];
         if (verbBuilder is UpdateVerbBuilder &&
-            verbBuilder.atKeyObj.toString() == 'public:publickey$atSign') {
-          ttrOfPublicKeyFromUpdateVerbBuilder = verbBuilder.metadata.ttr;
+            verbBuilder.atKey.toString() == 'public:publickey$atSign') {
+          ttrOfPublicKeyFromUpdateVerbBuilder = verbBuilder.atKey.metadata.ttr;
         }
         return 'data:1';
       });
diff --git a/tests/at_end2end_test/pubspec.yaml b/tests/at_end2end_test/pubspec.yaml
index fc9af626f..ec15fb80d 100644
--- a/tests/at_end2end_test/pubspec.yaml
+++ b/tests/at_end2end_test/pubspec.yaml
@@ -13,7 +13,25 @@ dependencies:
   at_client:
     path: ../../packages/at_client
 
+dependency_overrides:
+  at_persistence_secondary_server:
+    git:
+      url: https://github.com/atsign-foundation/at_server.git
+      path: packages/at_persistence_secondary_server
+      ref: uptake_commons_4.0.0
+  at_lookup:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_lookup
+      ref: srk_commons_changes
+  at_commons:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_commons
+      ref: srk_commons_changes
+  watcher: ^1.1.0
+
 dev_dependencies:
-  test: ^1.24.3
+  test: ^1.24.9
   lints: ^2.0.0
   coverage: ^1.5.0
diff --git a/tests/at_functional_test/pubspec.yaml b/tests/at_functional_test/pubspec.yaml
index 095a0fe30..792bc059c 100644
--- a/tests/at_functional_test/pubspec.yaml
+++ b/tests/at_functional_test/pubspec.yaml
@@ -10,6 +10,24 @@ dependencies:
   uuid: 3.0.7
   at_client:
     path: ../../packages/at_client
+  at_chops: ^1.0.6
+
+dependency_overrides:
+  at_persistence_secondary_server:
+    git:
+      url: https://github.com/atsign-foundation/at_server.git
+      path: packages/at_persistence_secondary_server
+      ref: uptake_commons_4.0.0
+  at_lookup:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_lookup
+      ref: srk_commons_changes
+  at_commons:
+    git:
+      url: https://github.com/atsign-foundation/at_libraries.git
+      path: packages/at_commons
+      ref: srk_commons_changes
 
 dev_dependencies:
   test: ^1.24.3
diff --git a/tests/at_functional_test/test/at_client_sync_test.dart b/tests/at_functional_test/test/at_client_sync_test.dart
index ab9214c95..0b0e3dfb2 100644
--- a/tests/at_functional_test/test/at_client_sync_test.dart
+++ b/tests/at_functional_test/test/at_client_sync_test.dart
@@ -46,9 +46,10 @@ void main() {
     expect(serverCommitIdAfterPut! > serverCommitId!, true);
     // Getting value from remote secondary
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'twitter.wavi'
-      ..sharedWith = sharedWithAtSign
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'twitter.wavi'
+        ..sharedWith = sharedWithAtSign
+        ..sharedBy = atSign)
       ..operation = 'all';
     var getResponse =
         await atClient.getRemoteSecondary()!.executeVerb(llookupVerbBuilder);
@@ -68,17 +69,15 @@ void main() {
     // twitter.me@alice🛠
     var value = 'alice.linkedin';
     var updateVerbBuilder = UpdateVerbBuilder()
-      ..atKeyObj =
-          AtKey.public('linkedin', namespace: namespace, sharedBy: atSign)
-              .build()
+      ..atKey = AtKey.public('linkedin', namespace: namespace, sharedBy: atSign)
+          .build()
       ..value = value;
     var updateResponse =
         await atClient.getRemoteSecondary()!.executeVerb(updateVerbBuilder);
     expect(updateResponse.isNotEmpty, true);
     // Waits until key is synced to the remote secondary
     await FunctionalTestSyncService.getInstance().syncData(atClient.syncService,
-        syncOptions: SyncOptions()
-          ..key = updateVerbBuilder.atKeyObj.toString());
+        syncOptions: SyncOptions()..key = updateVerbBuilder.atKey.toString());
     // Getting server commit id after put
     var localEntryAfterSync =
         await SyncUtil().getLastSyncedEntry('', atSign: atSign);
@@ -136,9 +135,10 @@ void main() {
     expect(serverCommitIdAfterPut! > serverCommitId!, true);
     // Getting value from remote secondary
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'quora.wavi'
-      ..sharedWith = sharedWithAtSign
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'quora.wavi'
+        ..sharedWith = sharedWithAtSign
+        ..sharedBy = atSign)
       ..operation = 'all';
     var getResponse =
         await atClient.getRemoteSecondary()!.executeVerb(llookupVerbBuilder);
@@ -165,9 +165,10 @@ void main() {
     await FunctionalTestSyncService.getInstance().syncData(atClient.syncService,
         syncOptions: SyncOptions()..key = atKey.toString());
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'discord.wavi'
-      ..sharedWith = sharedWithAtSign
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'discord.wavi'
+        ..sharedWith = sharedWithAtSign
+        ..sharedBy = atSign)
       ..operation = 'all';
     var getResponse =
         await atClient.getRemoteSecondary()!.executeVerb(llookupVerbBuilder);
@@ -196,8 +197,9 @@ void main() {
     expect(localEntryAfterSync!.atKey, isNot('local:localkey.wavi$atSign'));
     print('local synced entry $localEntryAfterSync');
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'local:localkey.wavi'
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'local:localkey.wavi'
+        ..sharedBy = atSign)
       ..operation = 'all';
     expect(
         () async => await atClient
@@ -223,8 +225,9 @@ void main() {
     await FunctionalTestSyncService.getInstance().syncData(atClient.syncService,
         syncOptions: SyncOptions()..key = atKey.toString());
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'key1.wavi'
-      ..sharedBy = atSign
+      ..atKey = (AtKey()
+        ..key = 'key1.wavi'
+        ..sharedBy = atSign)
       ..operation = 'all';
     var getResponse =
         await atClient.getRemoteSecondary()!.executeVerb(llookupVerbBuilder);
@@ -244,7 +247,7 @@ void main() {
     var putResult = await atClient.put(atKey, value);
     expect(putResult, true);
     var updateVerbBuilder = UpdateVerbBuilder()
-      ..atKeyObj = atKey
+      ..atKey = atKey
       ..value = value;
     var updateResponse =
         await atClient.getRemoteSecondary()!.executeVerb(updateVerbBuilder);
@@ -254,10 +257,11 @@ void main() {
         syncOptions: SyncOptions()..key = atKey.toString());
 
     var llookupVerbBuilder = LLookupVerbBuilder()
-      ..atKey = 'testkey.wavi'
-      ..sharedBy = atSign
-      ..operation = 'all'
-      ..isPublic = true;
+      ..atKey = (AtKey()
+        ..key = 'testkey.wavi'
+        ..sharedBy = atSign
+        ..metadata = (Metadata()..isPublic = true))
+      ..operation = 'all';
     var getResponse =
         await atClient.getRemoteSecondary()!.executeVerb(llookupVerbBuilder);
     var transformedValue =
diff --git a/tests/at_functional_test/test/atclient_remote_secondary_test.dart b/tests/at_functional_test/test/atclient_remote_secondary_test.dart
index 64ee841d9..32700c9fe 100644
--- a/tests/at_functional_test/test/atclient_remote_secondary_test.dart
+++ b/tests/at_functional_test/test/atclient_remote_secondary_test.dart
@@ -19,43 +19,44 @@ void main() {
   test('sequence of put and get results', () async {
     var value = '+1 1111';
     final phoneUpdateBuilder = UpdateVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'phone'
+      ..atKey = (AtKey()..key = 'phone'
       ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true))
       ..value = value;
     await atClientManager.atClient
         .getRemoteSecondary()!
         .executeVerb(phoneUpdateBuilder);
     final phoneLookupVerbBuilder = LLookupVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'phone'
-      ..sharedBy = atSign;
+      ..atKey = (AtKey()..key = 'phone'
+      ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true));
 
     final emailUpdateBuilder = UpdateVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'email'
+      ..atKey = (AtKey()..key = 'email'
       ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true))
       ..value = 'alice@gmail.com';
     await atClientManager.atClient
         .getRemoteSecondary()!
         .executeVerb(emailUpdateBuilder);
     final emailLookupVerbBuilder = LLookupVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'email'
-      ..sharedBy = atSign;
+
+      ..atKey = (AtKey()..key = 'email'
+      ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true));
 
     final locationUpdateBuilder = UpdateVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'location'
+      ..atKey = (AtKey()..key = 'location'
       ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true))
       ..value = 'newyork';
     await atClientManager.atClient
         .getRemoteSecondary()!
         .executeVerb(locationUpdateBuilder);
     final locationLookupVerbBuilder = LLookupVerbBuilder()
-      ..isPublic = true
-      ..atKey = 'location'
-      ..sharedBy = atSign;
+      ..atKey = (AtKey()..key = 'location'
+      ..sharedBy = atSign
+      ..metadata = (Metadata()..isPublic = true));
     final phoneFuture = atClientManager.atClient
         .getRemoteSecondary()!
         .executeVerb(phoneLookupVerbBuilder);
diff --git a/tests/at_functional_test/test/atclient_sync_callback_test.dart b/tests/at_functional_test/test/atclient_sync_callback_test.dart
index 42774582d..2bbfb604f 100644
--- a/tests/at_functional_test/test/atclient_sync_callback_test.dart
+++ b/tests/at_functional_test/test/atclient_sync_callback_test.dart
@@ -129,9 +129,10 @@ void main() {
     // username.me@alice🛠
     var value = 'alice_1231';
     var updateVerbBuilder = UpdateVerbBuilder()
-      ..atKey = 'fb_username-$uniqueId'
-      ..sharedBy = atSign
-      ..isPublic = true
+      ..atKey = (AtKey()
+        ..key = 'fb_username-$uniqueId'
+        ..sharedBy = atSign
+        ..metadata = (Metadata()..isPublic = true))
       ..value = value;
     var updateResponse = await atClientManager.atClient
         .getRemoteSecondary()!
diff --git a/tests/at_functional_test/test/atclient_sync_conflict_test.dart b/tests/at_functional_test/test/atclient_sync_conflict_test.dart
index d09261f73..b4a43ef28 100644
--- a/tests/at_functional_test/test/atclient_sync_conflict_test.dart
+++ b/tests/at_functional_test/test/atclient_sync_conflict_test.dart
@@ -37,10 +37,12 @@ void main() async {
     // Update the key directly to remote secondary for having
     // the conflict key during sync
     final updateVerbBuilder = UpdateVerbBuilder()
-      ..sharedBy = atSign
-      ..atKey = 'phone_0.wavi'
-      ..value = 'sMBnYFctMOg+lqX67ah9UA==' //encrypted value of 4
-      ..isEncrypted = true;
+      ..atKey = (AtKey()
+        ..key = 'phone_0.wavi'
+        ..sharedBy = atSign
+        ..metadata = (Metadata()..isEncrypted = true))
+      ..value = 'sMBnYFctMOg+lqX67ah9UA=='; //encrypted value of 4
+
     await atClientManager.atClient
         .getRemoteSecondary()!
         .executeVerb(updateVerbBuilder);
@@ -80,10 +82,12 @@ void main() async {
     // conflicting key during sync
     final remoteSecondary = atClientManager.atClient.getRemoteSecondary()!;
     final updateVerbBuilder = UpdateVerbBuilder()
-      ..sharedBy = atSign
-      ..atKey = 'test.$namespace'
-      ..ttl = 2
-      ..isPublic = true
+      ..atKey = (AtKey()
+        ..key = 'test.$namespace'
+        ..sharedBy = atSign
+        ..metadata = (Metadata()
+          ..ttl = 2
+          ..isPublic = true))
       ..value = 'randomvalue';
     await remoteSecondary.executeVerb(updateVerbBuilder);
     // Wait for 12 milliseconds to the key to expire
diff --git a/tests/at_functional_test/test/encryption_test.dart b/tests/at_functional_test/test/encryption_test.dart
index 34ea7c832..740855ced 100644
--- a/tests/at_functional_test/test/encryption_test.dart
+++ b/tests/at_functional_test/test/encryption_test.dart
@@ -1,19 +1,19 @@
 import 'package:at_client/at_client.dart';
 import 'package:at_functional_test/src/config_util.dart';
 import 'package:at_utils/at_utils.dart';
-import 'test_utils.dart';
 import 'package:test/test.dart';
 import 'package:version/version.dart';
 
+import 'test_utils.dart';
+
 void main() {
   late String atSign_1;
   final namespace = 'e2e_encryption_test';
 
-
   var clearText = 'Some clear text';
 
   var logLevelToRestore = AtSignLogger.root_level;
-  
+
   setUpAll(() async {
     AtSignLogger.root_level = 'SHOUT';
     atSign_1 = ConfigUtil.getYaml()['atSign']['firstAtSign'];
@@ -25,9 +25,7 @@ void main() {
 
   Future<AtClient> getAtClient(String atSign, Version version) async {
     AtClient atClient = (await AtClientManager.getInstance().setCurrentAtSign(
-            atSign,
-            namespace,
-          TestUtils.getPreference(atSign_1)))
+            atSign, namespace, TestUtils.getPreference(atSign_1)))
         .atClient;
 
     atClient.getPreferences()!.atProtocolEmitted = version;
@@ -42,7 +40,7 @@ void main() {
 
       var atKey = (AtKey.self('test_put.15_15')..timeToLive(ttl)).build();
       await atClient.put(atKey, clearText);
-      expect(atKey.metadata?.ivNonce, isNull);
+      expect(atKey.metadata.ivNonce, isNull);
 
       atClient.getPreferences()!.atProtocolEmitted = Version(1, 5, 0);
 
@@ -63,7 +61,7 @@ void main() {
 
       var atKey = (AtKey.self('test_put.15_20')..timeToLive(ttl)).build();
       await atClient.put(atKey, clearText);
-      expect(atKey.metadata?.ivNonce, isNull);
+      expect(atKey.metadata.ivNonce, isNull);
 
       atClient.getPreferences()!.atProtocolEmitted = Version(2, 0, 0);
       String selfEncryptionKey =
@@ -83,7 +81,7 @@ void main() {
 
       var atKey = (AtKey.self('test_put.20_20')..timeToLive(ttl)).build();
       await atClient.put(atKey, clearText);
-      expect(atKey.metadata?.ivNonce, isNotNull);
+      expect(atKey.metadata.ivNonce, isNotNull);
 
       atClient.getPreferences()!.atProtocolEmitted = Version(2, 0, 0);
       String selfEncryptionKey =
@@ -93,7 +91,7 @@ void main() {
       var cipherText = atData.data;
       expect(
           EncryptionUtil.decryptValue(cipherText, selfEncryptionKey,
-              ivBase64: atKey.metadata?.ivNonce),
+              ivBase64: atKey.metadata.ivNonce),
           clearText);
 
       var getResult = await atClient.get(atKey);
@@ -105,7 +103,7 @@ void main() {
 
       var atKey = (AtKey.self('test_put.20_15')..timeToLive(ttl)).build();
       await atClient.put(atKey, clearText);
-      expect(atKey.metadata?.ivNonce, isNotNull);
+      expect(atKey.metadata.ivNonce, isNotNull);
 
       atClient.getPreferences()!.atProtocolEmitted = Version(1, 5, 0);
       String selfEncryptionKey =
@@ -115,7 +113,7 @@ void main() {
       var cipherText = atData.data;
       expect(
           EncryptionUtil.decryptValue(cipherText, selfEncryptionKey,
-              ivBase64: atKey.metadata?.ivNonce),
+              ivBase64: atKey.metadata.ivNonce),
           clearText);
 
       var getResult = await atClient.get(atKey);