diff --git a/Cargo.toml b/Cargo.toml
index 65f0f7695..fe14e7ed4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -90,8 +90,7 @@ ibc-client-tendermint-types = { version = "0.49.1", path = "./ibc-clients/ics07-
 ibc-app-transfer-types      = { version = "0.49.1", path = "./ibc-apps/ics20-transfer/types", default-features = false }
 ibc-app-nft-transfer-types  = { version = "0.49.1", path = "./ibc-apps/ics721-nft-transfer/types", default-features = false }
 
-#ibc-proto = { version = "0.39.1", default-features = false }
-ibc-proto = { git = "https://github.com/heliaxdev/ibc-proto-rs", branch = "yuji/feat/ics721-impl", default-features = false }
+ibc-proto = { version = "0.41.0", default-features = false }
 
 # cosmos dependencies
 tendermint                       = { version = "0.34.0", default-features = false }
diff --git a/ibc-apps/ics721-nft-transfer/src/context.rs b/ibc-apps/ics721-nft-transfer/src/context.rs
index 508f94b6b..34fec88dd 100644
--- a/ibc-apps/ics721-nft-transfer/src/context.rs
+++ b/ibc-apps/ics721-nft-transfer/src/context.rs
@@ -17,10 +17,10 @@ pub trait NftContext {
     fn get_id(&self) -> &TokenId;
 
     /// Get the token URI
-    fn get_uri(&self) -> &TokenUri;
+    fn get_uri(&self) -> Option<&TokenUri>;
 
     /// Get the token Data
-    fn get_data(&self) -> &TokenData;
+    fn get_data(&self) -> Option<&TokenData>;
 }
 
 pub trait NftClassContext {
@@ -28,10 +28,10 @@ pub trait NftClassContext {
     fn get_id(&self) -> &ClassId;
 
     /// Get the class URI
-    fn get_uri(&self) -> &ClassUri;
+    fn get_uri(&self) -> Option<&ClassUri>;
 
     /// Get the class Data
-    fn get_data(&self) -> &ClassData;
+    fn get_data(&self) -> Option<&ClassData>;
 }
 
 /// Read-only methods required in NFT transfer validation context.
@@ -50,11 +50,18 @@ pub trait NftTransferValidationContext {
     fn can_receive_nft(&self) -> Result<(), NftTransferError>;
 
     /// Validates that the NFT can be created or updated successfully.
+    ///
+    /// Note: some existing ICS-721 implementations may not strictly adhere to
+    /// the ICS-721 class data structure. The
+    /// [`ClassData`] associated with this
+    /// implementation can take any valid JSON format. If your project requires
+    /// ICS-721 format for the `ClassData`, ensure correctness by checking with
+    /// [`parse_as_ics721_data()`](crate::types::Data::parse_as_ics721_data).
     fn create_or_update_class_validate(
         &self,
         class_id: &PrefixedClassId,
-        class_uri: &ClassUri,
-        class_data: &ClassData,
+        class_uri: Option<&ClassUri>,
+        class_data: Option<&ClassData>,
     ) -> Result<(), NftTransferError>;
 
     /// Validates that the tokens can be escrowed successfully.
@@ -83,13 +90,20 @@ pub trait NftTransferValidationContext {
     ) -> Result<(), NftTransferError>;
 
     /// Validates the receiver account and the NFT input
+    ///
+    /// Note: some existing ICS-721 implementations may not strictly adhere to
+    /// the ICS-721 token data structure. The
+    /// [`TokenData`] associated with this
+    /// implementation can take any valid JSON format. If your project requires
+    /// ICS-721 format for `TokenData`, ensure correctness by checking with
+    /// [`parse_as_ics721_data()`](crate::types::Data::parse_as_ics721_data).
     fn mint_nft_validate(
         &self,
         account: &Self::AccountId,
         class_id: &PrefixedClassId,
         token_id: &TokenId,
-        token_uri: &TokenUri,
-        token_data: &TokenData,
+        token_uri: Option<&TokenUri>,
+        token_data: Option<&TokenData>,
     ) -> Result<(), NftTransferError>;
 
     /// Validates the sender account and the coin input before burning.
@@ -133,8 +147,8 @@ pub trait NftTransferExecutionContext: NftTransferValidationContext {
     fn create_or_update_class_execute(
         &self,
         class_id: &PrefixedClassId,
-        class_uri: &ClassUri,
-        class_data: &ClassData,
+        class_uri: Option<&ClassUri>,
+        class_data: Option<&ClassData>,
     ) -> Result<(), NftTransferError>;
 
     /// Executes the escrow of the NFT in a user account.
@@ -167,8 +181,8 @@ pub trait NftTransferExecutionContext: NftTransferValidationContext {
         account: &Self::AccountId,
         class_id: &PrefixedClassId,
         token_id: &TokenId,
-        token_uri: &TokenUri,
-        token_data: &TokenData,
+        token_uri: Option<&TokenUri>,
+        token_data: Option<&TokenData>,
     ) -> Result<(), NftTransferError>;
 
     /// Executes burning of the NFT in a user account.
diff --git a/ibc-apps/ics721-nft-transfer/src/handler/mod.rs b/ibc-apps/ics721-nft-transfer/src/handler/mod.rs
index 3d577b709..2adbb47f6 100644
--- a/ibc-apps/ics721-nft-transfer/src/handler/mod.rs
+++ b/ibc-apps/ics721-nft-transfer/src/handler/mod.rs
@@ -40,14 +40,12 @@ pub fn refund_packet_nft_execute(
     }
     // mint vouchers back to sender
     else {
-        data.token_ids
-            .0
-            .iter()
-            .zip(data.token_uris.iter())
-            .zip(data.token_data.iter())
-            .try_for_each(|((token_id, token_uri), token_data)| {
-                ctx_a.mint_nft_execute(&sender, &data.class_id, token_id, token_uri, token_data)
-            })
+        for (i, token_id) in data.token_ids.0.iter().enumerate() {
+            let token_uri = data.token_uris.as_ref().and_then(|uris| uris.get(i));
+            let token_data = data.token_data.as_ref().and_then(|data| data.get(i));
+            ctx_a.mint_nft_execute(&sender, &data.class_id, token_id, token_uri, token_data)?;
+        }
+        Ok(())
     }
 }
 
@@ -77,13 +75,11 @@ pub fn refund_packet_nft_validate(
             )
         })
     } else {
-        data.token_ids
-            .0
-            .iter()
-            .zip(data.token_uris.iter())
-            .zip(data.token_data.iter())
-            .try_for_each(|((token_id, token_uri), token_data)| {
-                ctx_a.mint_nft_validate(&sender, &data.class_id, token_id, token_uri, token_data)
-            })
+        for (i, token_id) in data.token_ids.0.iter().enumerate() {
+            let token_uri = data.token_uris.as_ref().and_then(|uris| uris.get(i));
+            let token_data = data.token_data.as_ref().and_then(|data| data.get(i));
+            ctx_a.mint_nft_validate(&sender, &data.class_id, token_id, token_uri, token_data)?;
+        }
+        Ok(())
     }
 }
diff --git a/ibc-apps/ics721-nft-transfer/src/handler/on_recv_packet.rs b/ibc-apps/ics721-nft-transfer/src/handler/on_recv_packet.rs
index 768a7f757..8782bf7a2 100644
--- a/ibc-apps/ics721-nft-transfer/src/handler/on_recv_packet.rs
+++ b/ibc-apps/ics721-nft-transfer/src/handler/on_recv_packet.rs
@@ -81,13 +81,10 @@ where
             events: vec![],
             log: Vec::new(),
         };
-        for ((token_id, token_uri), token_data) in data
-            .token_ids
-            .0
-            .iter()
-            .zip(data.token_uris.iter())
-            .zip(data.token_data.iter())
-        {
+        for (i, token_id) in data.token_ids.0.iter().enumerate() {
+            let token_uri = data.token_uris.as_ref().and_then(|uris| uris.get(i));
+            let token_data = data.token_data.as_ref().and_then(|data| data.get(i));
+
             let trace_event = TokenTraceEvent {
                 trace_hash: ctx_b.token_hash_string(&class_id, token_id),
                 class: class_id.clone(),
@@ -98,19 +95,19 @@ where
             // Note: the validation is called before the execution.
             // Refer to ICS-20 `process_recv_packet_execute()`.
 
-            let class_uri = data
-                .class_uri
-                .as_ref()
-                .ok_or((ModuleExtras::empty(), NftTransferError::NftClassNotFound))?;
-            let class_data = data
-                .class_data
-                .as_ref()
-                .ok_or((ModuleExtras::empty(), NftTransferError::NftClassNotFound))?;
             ctx_b
-                .create_or_update_class_validate(&class_id, class_uri, class_data)
+                .create_or_update_class_validate(
+                    &class_id,
+                    data.class_uri.as_ref(),
+                    data.class_data.as_ref(),
+                )
                 .map_err(|nft_error| (ModuleExtras::empty(), nft_error))?;
             ctx_b
-                .create_or_update_class_execute(&class_id, class_uri, class_data)
+                .create_or_update_class_execute(
+                    &class_id,
+                    data.class_uri.as_ref(),
+                    data.class_data.as_ref(),
+                )
                 .map_err(|nft_error| (ModuleExtras::empty(), nft_error))?;
 
             ctx_b
diff --git a/ibc-apps/ics721-nft-transfer/src/handler/send_transfer.rs b/ibc-apps/ics721-nft-transfer/src/handler/send_transfer.rs
index a197bee5c..270164701 100644
--- a/ibc-apps/ics721-nft-transfer/src/handler/send_transfer.rs
+++ b/ibc-apps/ics721-nft-transfer/src/handler/send_transfer.rs
@@ -67,8 +67,12 @@ where
     let class_id = &packet_data.class_id;
     let token_ids = &packet_data.token_ids;
     // overwrite even if they are set in MsgTransfer
-    packet_data.token_uris.clear();
-    packet_data.token_data.clear();
+    if let Some(uris) = &mut packet_data.token_uris {
+        uris.clear();
+    }
+    if let Some(data) = &mut packet_data.token_data {
+        data.clear();
+    }
     for token_id in token_ids.as_ref() {
         if is_sender_chain_source(msg.port_id_on_a.clone(), msg.chan_id_on_a.clone(), class_id) {
             transfer_ctx.escrow_nft_validate(
@@ -77,19 +81,35 @@ where
                 &msg.chan_id_on_a,
                 class_id,
                 token_id,
-                &packet_data.memo,
+                &packet_data.memo.clone().unwrap_or_default(),
             )?;
         } else {
-            transfer_ctx.burn_nft_validate(&sender, class_id, token_id, &packet_data.memo)?;
+            transfer_ctx.burn_nft_validate(
+                &sender,
+                class_id,
+                token_id,
+                &packet_data.memo.clone().unwrap_or_default(),
+            )?;
         }
         let nft = transfer_ctx.get_nft(class_id, token_id)?;
-        packet_data.token_uris.push(nft.get_uri().clone());
-        packet_data.token_data.push(nft.get_data().clone());
+        // Set the URI and the data if both exists
+        if let (Some(uri), Some(data)) = (nft.get_uri(), nft.get_data()) {
+            match &mut packet_data.token_uris {
+                Some(uris) => uris.push(uri.clone()),
+                None => packet_data.token_uris = Some(vec![uri.clone()]),
+            }
+            match &mut packet_data.token_data {
+                Some(token_data) => token_data.push(data.clone()),
+                None => packet_data.token_data = Some(vec![data.clone()]),
+            }
+        }
     }
 
+    packet_data.validate_basic()?;
+
     let nft_class = transfer_ctx.get_nft_class(class_id)?;
-    packet_data.class_uri = Some(nft_class.get_uri().clone());
-    packet_data.class_data = Some(nft_class.get_data().clone());
+    packet_data.class_uri = nft_class.get_uri().cloned();
+    packet_data.class_data = nft_class.get_data().cloned();
 
     let packet = {
         let data = serde_json::to_vec(&packet_data)
@@ -150,8 +170,12 @@ where
     let class_id = &packet_data.class_id;
     let token_ids = &packet_data.token_ids;
     // overwrite even if they are set in MsgTransfer
-    packet_data.token_uris.clear();
-    packet_data.token_data.clear();
+    if let Some(uris) = &mut packet_data.token_uris {
+        uris.clear();
+    }
+    if let Some(data) = &mut packet_data.token_data {
+        data.clear();
+    }
     for token_id in token_ids.as_ref() {
         if is_sender_chain_source(msg.port_id_on_a.clone(), msg.chan_id_on_a.clone(), class_id) {
             transfer_ctx.escrow_nft_execute(
@@ -160,19 +184,33 @@ where
                 &msg.chan_id_on_a,
                 class_id,
                 token_id,
-                &packet_data.memo,
+                &packet_data.memo.clone().unwrap_or_default(),
             )?;
         } else {
-            transfer_ctx.burn_nft_execute(&sender, class_id, token_id, &packet_data.memo)?;
+            transfer_ctx.burn_nft_execute(
+                &sender,
+                class_id,
+                token_id,
+                &packet_data.memo.clone().unwrap_or_default(),
+            )?;
         }
         let nft = transfer_ctx.get_nft(class_id, token_id)?;
-        packet_data.token_uris.push(nft.get_uri().clone());
-        packet_data.token_data.push(nft.get_data().clone());
+        // Set the URI and the data if both exists
+        if let (Some(uri), Some(data)) = (nft.get_uri(), nft.get_data()) {
+            match &mut packet_data.token_uris {
+                Some(uris) => uris.push(uri.clone()),
+                None => packet_data.token_uris = Some(vec![uri.clone()]),
+            }
+            match &mut packet_data.token_data {
+                Some(token_data) => token_data.push(data.clone()),
+                None => packet_data.token_data = Some(vec![data.clone()]),
+            }
+        }
     }
 
     let nft_class = transfer_ctx.get_nft_class(class_id)?;
-    packet_data.class_uri = Some(nft_class.get_uri().clone());
-    packet_data.class_data = Some(nft_class.get_data().clone());
+    packet_data.class_uri = nft_class.get_uri().cloned();
+    packet_data.class_data = nft_class.get_data().cloned();
 
     let packet = {
         let data = {
@@ -204,7 +242,7 @@ where
             receiver: packet_data.receiver,
             class: packet_data.class_id,
             tokens: packet_data.token_ids,
-            memo: packet_data.memo,
+            memo: packet_data.memo.unwrap_or_default(),
         };
         send_packet_ctx_a.emit_ibc_event(ModuleEvent::from(transfer_event).into())?;
 
diff --git a/ibc-apps/ics721-nft-transfer/src/module.rs b/ibc-apps/ics721-nft-transfer/src/module.rs
index efbd10b18..fc4097016 100644
--- a/ibc-apps/ics721-nft-transfer/src/module.rs
+++ b/ibc-apps/ics721-nft-transfer/src/module.rs
@@ -194,7 +194,7 @@ pub fn on_recv_packet_execute(
         receiver: data.receiver,
         class: data.class_id,
         tokens: data.token_ids,
-        memo: data.memo,
+        memo: data.memo.unwrap_or_default(),
         success: ack.is_successful(),
     };
     extras.events.push(recv_event.into());
@@ -259,7 +259,7 @@ pub fn on_acknowledgement_packet_execute(
         receiver: data.receiver,
         class: data.class_id,
         tokens: data.token_ids,
-        memo: data.memo,
+        memo: data.memo.unwrap_or_default(),
         acknowledgement: acknowledgement.clone(),
     };
 
@@ -307,7 +307,7 @@ pub fn on_timeout_packet_execute(
         refund_receiver: data.sender,
         refund_class: data.class_id,
         refund_tokens: data.token_ids,
-        memo: data.memo,
+        memo: data.memo.unwrap_or_default(),
     };
 
     let extras = ModuleExtras {
diff --git a/ibc-apps/ics721-nft-transfer/types/src/class.rs b/ibc-apps/ics721-nft-transfer/types/src/class.rs
index f5d5e590f..278a90a07 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/class.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/class.rs
@@ -419,7 +419,7 @@ impl FromStr for ClassUri {
 )]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, derive_more::AsRef)]
 pub struct ClassData(Data);
 
 impl Display for ClassData {
diff --git a/ibc-apps/ics721-nft-transfer/types/src/data.rs b/ibc-apps/ics721-nft-transfer/types/src/data.rs
index a5fe516c0..098c8c094 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/data.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/data.rs
@@ -2,11 +2,73 @@
 use core::fmt::{self, Display, Formatter};
 use core::str::FromStr;
 
+use base64::prelude::BASE64_STANDARD;
+use base64::Engine;
 use ibc_core::primitives::prelude::*;
 use mime::Mime;
 
 use crate::error::NftTransferError;
 
+#[cfg_attr(
+    feature = "parity-scale-codec",
+    derive(
+        parity_scale_codec::Encode,
+        parity_scale_codec::Decode,
+        scale_info::TypeInfo
+    )
+)]
+#[cfg_attr(
+    feature = "borsh",
+    derive(borsh::BorshSerialize, borsh::BorshDeserialize)
+)]
+#[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
+#[derive(Clone, Debug, Default, PartialEq, Eq, derive_more::From)]
+pub struct Data(String);
+
+impl Data {
+    /// Parses the data in the format specified by ICS-721.
+    pub fn parse_as_ics721_data(&self) -> Result<Ics721Data, NftTransferError> {
+        self.0.parse::<Ics721Data>()
+    }
+}
+
+impl Display for Data {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl FromStr for Data {
+    type Err = NftTransferError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(Self(s.to_string()))
+    }
+}
+
+impl serde::Serialize for Data {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&BASE64_STANDARD.encode(&self.0))
+    }
+}
+
+impl<'de> serde::Deserialize<'de> for Data {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let encoded = String::deserialize(deserializer)?;
+        let decoded = BASE64_STANDARD
+            .decode(encoded)
+            .map_err(serde::de::Error::custom)?;
+        let decoded_str = String::from_utf8(decoded).map_err(serde::de::Error::custom)?;
+        Ok(Data(decoded_str))
+    }
+}
+
 #[cfg_attr(
     feature = "parity-scale-codec",
     derive(
@@ -22,7 +84,15 @@ use crate::error::NftTransferError;
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
 #[derive(Clone, Debug, Default, PartialEq, Eq)]
-pub struct Data(BTreeMap<String, DataValue>);
+pub struct Ics721Data(BTreeMap<String, DataValue>);
+
+impl FromStr for Ics721Data {
+    type Err = NftTransferError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        serde_json::from_str(s).map_err(|_| NftTransferError::InvalidIcs721Data)
+    }
+}
 
 #[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct DataValue {
@@ -169,23 +239,6 @@ impl schemars::JsonSchema for DataValue {
     }
 }
 
-impl Display for Data {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", serde_json::to_string(&self.0).expect("infallible"))
-    }
-}
-
-impl FromStr for Data {
-    type Err = NftTransferError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let data: BTreeMap<String, DataValue> =
-            serde_json::from_str(s).map_err(|_| NftTransferError::InvalidJsonData)?;
-
-        Ok(Self(data))
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use rstest::rstest;
diff --git a/ibc-apps/ics721-nft-transfer/types/src/error.rs b/ibc-apps/ics721-nft-transfer/types/src/error.rs
index fc3b03591..08ab598e5 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/error.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/error.rs
@@ -46,10 +46,12 @@ pub enum NftTransferError {
     InvalidTokenId,
     /// duplicated token IDs
     DuplicatedTokenIds,
-    /// invalid token ID
+    /// The length of token IDs mismatched that of token URIs or token data
     TokenMismatched,
     /// invalid json data
     InvalidJsonData,
+    /// the data is not in the JSON format specified by ICS-721
+    InvalidIcs721Data,
     /// expected `{expect_order}` channel, got `{got_order}`
     ChannelNotUnordered {
         expect_order: Order,
diff --git a/ibc-apps/ics721-nft-transfer/types/src/lib.rs b/ibc-apps/ics721-nft-transfer/types/src/lib.rs
index 74fed4f5e..b429ce1a3 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/lib.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/lib.rs
@@ -24,6 +24,8 @@ pub use class::*;
 #[cfg(feature = "serde")]
 mod data;
 #[cfg(feature = "serde")]
+pub use data::*;
+#[cfg(feature = "serde")]
 pub mod events;
 #[cfg(feature = "serde")]
 pub mod msgs;
diff --git a/ibc-apps/ics721-nft-transfer/types/src/memo.rs b/ibc-apps/ics721-nft-transfer/types/src/memo.rs
index 9db8e4e11..432dd4fc6 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/memo.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/memo.rs
@@ -24,7 +24,7 @@ use ibc_core::primitives::prelude::*;
 )]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct Memo(String);
 
 impl AsRef<str> for Memo {
diff --git a/ibc-apps/ics721-nft-transfer/types/src/msgs/transfer.rs b/ibc-apps/ics721-nft-transfer/types/src/msgs/transfer.rs
index 49ea39363..357723f61 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/msgs/transfer.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/msgs/transfer.rs
@@ -66,6 +66,12 @@ impl TryFrom<RawMsgTransfer> for MsgTransfer {
             return Err(ContextError::from(PacketError::MissingTimeout))?;
         }
 
+        let memo = if raw_msg.memo.is_empty() {
+            None
+        } else {
+            Some(raw_msg.memo.into())
+        };
+
         Ok(MsgTransfer {
             port_id_on_a: raw_msg.source_port.parse()?,
             chan_id_on_a: raw_msg.source_channel.parse()?,
@@ -74,11 +80,11 @@ impl TryFrom<RawMsgTransfer> for MsgTransfer {
                 class_uri: None,
                 class_data: None,
                 token_ids: raw_msg.token_ids.try_into()?,
-                token_uris: vec![],
-                token_data: vec![],
+                token_uris: None,
+                token_data: None,
                 sender: raw_msg.sender.into(),
                 receiver: raw_msg.receiver.into(),
-                memo: raw_msg.memo.into(),
+                memo,
             },
             timeout_height_on_b,
             timeout_timestamp_on_b,
@@ -103,7 +109,11 @@ impl From<MsgTransfer> for RawMsgTransfer {
             receiver: domain_msg.packet_data.receiver.to_string(),
             timeout_height: domain_msg.timeout_height_on_b.into(),
             timeout_timestamp: domain_msg.timeout_timestamp_on_b.nanoseconds(),
-            memo: domain_msg.packet_data.memo.to_string(),
+            memo: domain_msg
+                .packet_data
+                .memo
+                .map(|m| m.to_string())
+                .unwrap_or_default(),
         }
     }
 }
diff --git a/ibc-apps/ics721-nft-transfer/types/src/packet.rs b/ibc-apps/ics721-nft-transfer/types/src/packet.rs
index 7db6a3504..a870ae436 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/packet.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/packet.rs
@@ -11,14 +11,12 @@ use ibc_proto::ibc::applications::nft_transfer::v1::NonFungibleTokenPacketData a
 use crate::class::{ClassData, ClassUri, PrefixedClassId};
 use crate::error::NftTransferError;
 use crate::memo::Memo;
+use crate::serializers;
 use crate::token::{TokenData, TokenIds, TokenUri};
 
 /// Defines the structure of token transfers' packet bytes
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
-#[cfg_attr(
-    feature = "serde",
-    serde(try_from = "RawPacketData", into = "RawPacketData")
-)]
+#[serde(rename_all = "camelCase")]
 #[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
 #[cfg_attr(
     feature = "parity-scale-codec",
@@ -30,15 +28,19 @@ use crate::token::{TokenData, TokenIds, TokenUri};
 )]
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct PacketData {
+    #[cfg_attr(feature = "serde", serde(with = "serializers"))]
+    #[cfg_attr(feature = "schema", schemars(with = "String"))]
     pub class_id: PrefixedClassId,
     pub class_uri: Option<ClassUri>,
     pub class_data: Option<ClassData>,
     pub token_ids: TokenIds,
-    pub token_uris: Vec<TokenUri>,
-    pub token_data: Vec<TokenData>,
+    // Need `Option` to decode `null` value
+    pub token_uris: Option<Vec<TokenUri>>,
+    // Need `Option` to decode `null` value
+    pub token_data: Option<Vec<TokenData>>,
     pub sender: Signer,
     pub receiver: Signer,
-    pub memo: Memo,
+    pub memo: Option<Memo>,
 }
 
 impl PacketData {
@@ -54,16 +56,23 @@ impl PacketData {
         receiver: Signer,
         memo: Memo,
     ) -> Result<Self, NftTransferError> {
-        if token_ids.0.is_empty() {
-            return Err(NftTransferError::NoTokenId);
-        }
-        let num = token_ids.0.len();
-        let num_uri = token_uris.len();
-        let num_data = token_data.len();
-        if (num_uri != 0 && num_uri != num) || (num_data != 0 && num_data != num) {
-            return Err(NftTransferError::TokenMismatched);
-        }
-        Ok(Self {
+        let token_uris = if token_uris.is_empty() {
+            None
+        } else {
+            Some(token_uris)
+        };
+        let token_data = if token_data.is_empty() {
+            None
+        } else {
+            Some(token_data)
+        };
+        let memo = if memo.as_ref().is_empty() {
+            None
+        } else {
+            Some(memo)
+        };
+
+        let packet_data = Self {
             class_id,
             class_uri,
             class_data,
@@ -73,7 +82,33 @@ impl PacketData {
             sender,
             receiver,
             memo,
-        })
+        };
+
+        packet_data.validate_basic()?;
+
+        Ok(packet_data)
+    }
+
+    /// Performs the basic validation of the packet data fields.
+    pub fn validate_basic(&self) -> Result<(), NftTransferError> {
+        if self.token_ids.0.is_empty() {
+            return Err(NftTransferError::NoTokenId);
+        }
+        let num = self.token_ids.0.len();
+        let num_uri = self
+            .token_uris
+            .as_ref()
+            .map(|t| t.len())
+            .unwrap_or_default();
+        let num_data = self
+            .token_data
+            .as_ref()
+            .map(|t| t.len())
+            .unwrap_or_default();
+        if (num_uri != 0 && num_uri != num) || (num_data != 0 && num_data != num) {
+            return Err(NftTransferError::TokenMismatched);
+        }
+        Ok(())
     }
 }
 
@@ -144,15 +179,21 @@ impl From<PacketData> for RawPacketData {
                 .iter()
                 .map(|t| t.to_string())
                 .collect(),
-            token_uris: pkt_data.token_uris.iter().map(|t| t.to_string()).collect(),
+            token_uris: pkt_data
+                .token_uris
+                .map(|uris| uris.iter().map(|t| t.to_string()).collect())
+                .unwrap_or_default(),
             token_data: pkt_data
                 .token_data
-                .iter()
-                .map(|t| BASE64_STANDARD.encode(t.to_string()))
-                .collect(),
+                .map(|data| {
+                    data.iter()
+                        .map(|t| BASE64_STANDARD.encode(t.to_string()))
+                        .collect()
+                })
+                .unwrap_or_default(),
             sender: pkt_data.sender.to_string(),
             receiver: pkt_data.receiver.to_string(),
-            memo: pkt_data.memo.to_string(),
+            memo: pkt_data.memo.map(|m| m.to_string()).unwrap_or_default(),
         }
     }
 }
@@ -167,10 +208,10 @@ mod tests {
     const DUMMY_CLASS_ID: &str = "class";
     const DUMMY_URI: &str = "http://example.com";
     const DUMMY_DATA: &str =
-        r#"{"name":{"value":"Crypto Creatures"},"image":{"value":"binary","mime":"image/png"}}"#;
+        r#"{"image":{"value":"binary","mime":"image/png"},"name":{"value":"Crypto Creatures"}}"#;
 
     impl PacketData {
-        pub fn new_dummy() -> Self {
+        pub fn new_dummy(memo: Option<&str>) -> Self {
             let address: Signer = DUMMY_ADDRESS.to_string().into();
 
             Self {
@@ -179,17 +220,17 @@ mod tests {
                 class_data: Some(ClassData::from_str(DUMMY_DATA).unwrap()),
                 token_ids: TokenIds::try_from(vec!["token_0".to_string(), "token_1".to_string()])
                     .unwrap(),
-                token_uris: vec![
+                token_uris: Some(vec![
                     TokenUri::from_str(DUMMY_URI).unwrap(),
                     TokenUri::from_str(DUMMY_URI).unwrap(),
-                ],
-                token_data: vec![
+                ]),
+                token_data: Some(vec![
                     TokenData::from_str(DUMMY_DATA).unwrap(),
                     TokenData::from_str(DUMMY_DATA).unwrap(),
-                ],
+                ]),
                 sender: address.clone(),
                 receiver: address,
-                memo: "".to_string().into(),
+                memo: memo.map(|m| m.to_string().into()),
             }
         }
 
@@ -201,11 +242,11 @@ mod tests {
                 class_uri: None,
                 class_data: None,
                 token_ids: TokenIds::try_from(vec!["token_0".to_string()]).unwrap(),
-                token_uris: vec![],
-                token_data: vec![],
+                token_uris: None,
+                token_data: None,
                 sender: address.clone(),
                 receiver: address,
-                memo: "".to_string().into(),
+                memo: None,
             }
         }
 
@@ -216,6 +257,17 @@ mod tests {
 
         pub fn deser_json_assert_eq(&self, json: &str) {
             let deser: Self = serde_json::from_str(json).unwrap();
+
+            if let Some(data) = &deser.class_data {
+                assert!(data.as_ref().parse_as_ics721_data().is_ok());
+            };
+
+            if let Some(token_data) = &deser.token_data {
+                for data in token_data.iter() {
+                    assert!(data.as_ref().parse_as_ics721_data().is_ok());
+                }
+            }
+
             assert_eq!(&deser, self);
         }
     }
@@ -224,8 +276,12 @@ mod tests {
         r#"{"classId":"class","tokenIds":["token_0"],"sender":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","receiver":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng"}"#
     }
 
+    fn dummy_min_json_packet_data_with_null() -> &'static str {
+        r#"{"classId":"class","classUri":null,"classData":null,"tokenIds":["token_0"],"tokenUris":null,"tokenData":null,"sender":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","receiver":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng"}"#
+    }
+
     fn dummy_json_packet_data() -> &'static str {
-        r#"{"classId":"class","classUri":"http://example.com/","classData":"eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0=","tokenIds":["token_0","token_1"],"tokenUris":["http://example.com/","http://example.com/"],"tokenData":["eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0=","eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0="],"sender":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","receiver":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","memo":""}"#
+        r#"{"classId":"class","classUri":"http://example.com/","classData":"eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0=","tokenIds":["token_0","token_1"],"tokenUris":["http://example.com/","http://example.com/"],"tokenData":["eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0=","eyJpbWFnZSI6eyJ2YWx1ZSI6ImJpbmFyeSIsIm1pbWUiOiJpbWFnZS9wbmcifSwibmFtZSI6eyJ2YWx1ZSI6IkNyeXB0byBDcmVhdHVyZXMifX0="],"sender":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","receiver":"cosmos1wxeyh7zgn4tctjzs0vtqpc6p5cxq5t2muzl7ng","memo":"memo"}"#
     }
 
     fn dummy_json_packet_data_without_memo() -> &'static str {
@@ -236,16 +292,17 @@ mod tests {
     /// `RawPacketData` and then serializing that.
     #[test]
     fn test_packet_data_ser() {
-        PacketData::new_dummy().ser_json_assert_eq(dummy_json_packet_data());
+        PacketData::new_dummy(Some("memo")).ser_json_assert_eq(dummy_json_packet_data());
     }
 
     /// Ensures `PacketData` properly decodes from JSON by first deserializing to a
     /// `RawPacketData` and then converting from that.
     #[test]
     fn test_packet_data_deser() {
-        PacketData::new_dummy().deser_json_assert_eq(dummy_json_packet_data());
-        PacketData::new_dummy().deser_json_assert_eq(dummy_json_packet_data_without_memo());
+        PacketData::new_dummy(Some("memo")).deser_json_assert_eq(dummy_json_packet_data());
+        PacketData::new_dummy(None).deser_json_assert_eq(dummy_json_packet_data_without_memo());
         PacketData::new_min_dummy().deser_json_assert_eq(dummy_min_json_packet_data());
+        PacketData::new_min_dummy().deser_json_assert_eq(dummy_min_json_packet_data_with_null());
     }
 
     #[test]
diff --git a/ibc-apps/ics721-nft-transfer/types/src/token.rs b/ibc-apps/ics721-nft-transfer/types/src/token.rs
index ff8f407bb..4965d49be 100644
--- a/ibc-apps/ics721-nft-transfer/types/src/token.rs
+++ b/ibc-apps/ics721-nft-transfer/types/src/token.rs
@@ -202,7 +202,7 @@ impl FromStr for TokenUri {
 )]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "schema", derive(schemars::JsonSchema))]
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, derive_more::AsRef)]
 pub struct TokenData(Data);
 
 impl Display for TokenData {
diff --git a/ibc-testkit/src/testapp/ibc/applications/nft_transfer/context.rs b/ibc-testkit/src/testapp/ibc/applications/nft_transfer/context.rs
index 491ec9ca4..a526dcf45 100644
--- a/ibc-testkit/src/testapp/ibc/applications/nft_transfer/context.rs
+++ b/ibc-testkit/src/testapp/ibc/applications/nft_transfer/context.rs
@@ -20,12 +20,12 @@ impl NftContext for DummyNft {
         &self.token_id
     }
 
-    fn get_uri(&self) -> &TokenUri {
-        &self.token_uri
+    fn get_uri(&self) -> Option<&TokenUri> {
+        self.token_uri.as_ref()
     }
 
-    fn get_data(&self) -> &TokenData {
-        &self.token_data
+    fn get_data(&self) -> Option<&TokenData> {
+        self.token_data.as_ref()
     }
 }
 
@@ -34,12 +34,12 @@ impl NftClassContext for DummyNftClass {
         &self.class_id
     }
 
-    fn get_uri(&self) -> &ClassUri {
-        &self.class_uri
+    fn get_uri(&self) -> Option<&ClassUri> {
+        self.class_uri.as_ref()
     }
 
-    fn get_data(&self) -> &ClassData {
-        &self.class_data
+    fn get_data(&self) -> Option<&ClassData> {
+        self.class_data.as_ref()
     }
 }
 
@@ -63,8 +63,8 @@ impl NftTransferValidationContext for DummyNftTransferModule {
     fn create_or_update_class_validate(
         &self,
         _class_id: &PrefixedClassId,
-        _class_uri: &ClassUri,
-        _class_data: &ClassData,
+        _class_uri: Option<&ClassUri>,
+        _class_data: Option<&ClassData>,
     ) -> Result<(), NftTransferError> {
         Ok(())
     }
@@ -97,8 +97,8 @@ impl NftTransferValidationContext for DummyNftTransferModule {
         _account: &Self::AccountId,
         _class_id: &PrefixedClassId,
         _token_id: &TokenId,
-        _token_uri: &TokenUri,
-        _token_data: &TokenData,
+        _token_uri: Option<&TokenUri>,
+        _token_data: Option<&TokenData>,
     ) -> Result<(), NftTransferError> {
         Ok(())
     }
@@ -133,8 +133,8 @@ impl NftTransferExecutionContext for DummyNftTransferModule {
     fn create_or_update_class_execute(
         &self,
         _class_id: &PrefixedClassId,
-        _class_uri: &ClassUri,
-        _class_data: &ClassData,
+        _class_uri: Option<&ClassUri>,
+        _class_data: Option<&ClassData>,
     ) -> Result<(), NftTransferError> {
         Ok(())
     }
@@ -167,8 +167,8 @@ impl NftTransferExecutionContext for DummyNftTransferModule {
         _account: &Self::AccountId,
         _class_id: &PrefixedClassId,
         _token_id: &TokenId,
-        _token_uri: &TokenUri,
-        _token_data: &TokenData,
+        _token_uri: Option<&TokenUri>,
+        _token_data: Option<&TokenData>,
     ) -> Result<(), NftTransferError> {
         Ok(())
     }
diff --git a/ibc-testkit/src/testapp/ibc/applications/nft_transfer/types.rs b/ibc-testkit/src/testapp/ibc/applications/nft_transfer/types.rs
index 6eb65e285..6e282fe61 100644
--- a/ibc-testkit/src/testapp/ibc/applications/nft_transfer/types.rs
+++ b/ibc-testkit/src/testapp/ibc/applications/nft_transfer/types.rs
@@ -7,17 +7,17 @@ pub struct DummyNftTransferModule;
 pub struct DummyNft {
     pub class_id: ClassId,
     pub token_id: TokenId,
-    pub token_uri: TokenUri,
-    pub token_data: TokenData,
+    pub token_uri: Option<TokenUri>,
+    pub token_data: Option<TokenData>,
 }
 
 impl Default for DummyNft {
     fn default() -> Self {
         let class_id = "class_0".parse().expect("infallible");
         let token_id = "token_0".parse().expect("infallible");
-        let token_uri = "http://example.com".parse().expect("infallible");
+        let token_uri = Some("http://example.com".parse().expect("infallible"));
         let data = r#"{"name":{"value":"Crypto Creatures"},"image":{"value":"binary","mime":"image/png"}}"#;
-        let token_data = data.parse().expect("infallible");
+        let token_data = Some(data.parse().expect("infallible"));
         Self {
             class_id,
             token_id,
@@ -30,16 +30,16 @@ impl Default for DummyNft {
 #[derive(Debug)]
 pub struct DummyNftClass {
     pub class_id: ClassId,
-    pub class_uri: ClassUri,
-    pub class_data: ClassData,
+    pub class_uri: Option<ClassUri>,
+    pub class_data: Option<ClassData>,
 }
 
 impl Default for DummyNftClass {
     fn default() -> Self {
         let class_id = "class_0".parse().expect("infallible");
-        let class_uri = "http://example.com".parse().expect("infallible");
+        let class_uri = Some("http://example.com".parse().expect("infallible"));
         let data = r#"{"name":{"value":"Crypto Creatures"},"image":{"value":"binary","mime":"image/png"}}"#;
-        let class_data = data.parse().expect("infallible");
+        let class_data = Some(data.parse().expect("infallible"));
         Self {
             class_id,
             class_uri,