diff --git a/packages/orama/src/components/groups.ts b/packages/orama/src/components/groups.ts
index 393dbea02..40ce8d66f 100644
--- a/packages/orama/src/components/groups.ts
+++ b/packages/orama/src/components/groups.ts
@@ -32,7 +32,7 @@ const ALLOWED_TYPES = ['string', 'number', 'boolean']
 export async function getGroups<T extends AnyOrama, ResultDocument = TypedDocument<T>>(
   orama: T,
   results: TokenScore[],
-  groupBy: GroupByParams<ResultDocument>,
+  groupBy: GroupByParams<T, ResultDocument>,
 ): Promise<GroupResult<ResultDocument>> {
   const properties = groupBy.properties
   const propertiesLength = properties.length
diff --git a/packages/orama/src/methods/create.ts b/packages/orama/src/methods/create.ts
index 17b29728c..a446bb797 100644
--- a/packages/orama/src/methods/create.ts
+++ b/packages/orama/src/methods/create.ts
@@ -1,13 +1,14 @@
 import { formatElapsedTime, getDocumentIndexId, getDocumentProperties, validateSchema } from '../components/defaults.js'
-import { createDocumentsStore } from '../components/documents-store.js'
+import { DocumentsStore, createDocumentsStore } from '../components/documents-store.js'
 import { FUNCTION_COMPONENTS, OBJECT_COMPONENTS, SINGLE_OR_ARRAY_COMPONENTS } from '../components/hooks.js'
-import { createIndex } from '../components/index.js'
+import { Index, createIndex } from '../components/index.js'
 import { createInternalDocumentIDStore } from '../components/internal-document-id-store.js'
-import { createSorter } from '../components/sorter.js'
+import { Sorter, createSorter } from '../components/sorter.js'
 import { createTokenizer } from '../components/tokenizer/index.js'
 import { createError } from '../errors.js'
 import {
   AfterSearch,
+  AnySchema,
   ArrayCallbackComponents,
   Components,
   FunctionComponents,
@@ -84,11 +85,11 @@ function validateComponents<OramaSchema, TIndex, TDocumentStore, TSorter, TOrama
 }
 
 export async function create<
-  const OramaSchema,
-  TIndex,
-  TDocumentStore,
-  TSorter,
-  ResultOrama extends Orama<OramaSchema, TIndex, TDocumentStore, TSorter>> ({
+  const OramaSchema extends AnySchema,
+  TIndex = Index,
+  TDocumentStore = DocumentsStore,
+  TSorter = Sorter,
+  ResultOrama extends Orama<OramaSchema, TIndex, TDocumentStore, TSorter> = Orama<OramaSchema, TIndex, TDocumentStore, TSorter>> ({
   schema,
   sort,
   language,
diff --git a/packages/orama/src/methods/search.ts b/packages/orama/src/methods/search.ts
index 2efd63bca..ba38e03ea 100644
--- a/packages/orama/src/methods/search.ts
+++ b/packages/orama/src/methods/search.ts
@@ -12,11 +12,13 @@ import { createError } from '../errors.js'
 import type {
   AnyOrama,
   BM25Params,
+  ComparisonOperator,
   CustomSorterFunctionItem,
   ElapsedTime,
   IndexMap,
   Result,
   Results,
+  SchemaValidKeys,
   SearchContext,
   SearchParams,
   SearchableValue,
@@ -158,7 +160,8 @@ export async function search<T extends AnyOrama, ResultDocument = TypedDocument<
   let whereFiltersIDs: InternalDocumentID[] = []
 
   if (hasFilters) {
-    whereFiltersIDs = await orama.index.searchByWhereClause(context, index, params.where!)
+    const whereParams = params.where as unknown as Record<SchemaValidKeys<T>, boolean | string | string[] | ComparisonOperator>;
+    whereFiltersIDs = await orama.index.searchByWhereClause(context, index, whereParams)
   }
 
   const tokensLength = tokens.length
diff --git a/packages/orama/src/methods/serialization.ts b/packages/orama/src/methods/serialization.ts
index d81b8b902..48b299470 100644
--- a/packages/orama/src/methods/serialization.ts
+++ b/packages/orama/src/methods/serialization.ts
@@ -1,10 +1,12 @@
 import { AnyOrama } from '../types.js'
+import { Language } from '../index.js'
 
 export interface RawData {
   internalDocumentIDStore: unknown
   index: unknown
   docs: unknown
   sorting: unknown
+  language: Language
 }
 
 export async function load<T extends AnyOrama>(orama: T, raw: RawData): Promise<void> {
@@ -12,6 +14,7 @@ export async function load<T extends AnyOrama>(orama: T, raw: RawData): Promise<
   orama.data.index = await orama.index.load(orama.internalDocumentIDStore, raw.index)
   orama.data.docs = await orama.documentsStore.load(orama.internalDocumentIDStore, raw.docs)
   orama.data.sorting = await orama.sorter.load(orama.internalDocumentIDStore, raw.sorting)
+  orama.tokenizer.language = raw.language
 }
 
 export async function save<T extends AnyOrama>(orama: T): Promise<RawData> {
@@ -20,5 +23,6 @@ export async function save<T extends AnyOrama>(orama: T): Promise<RawData> {
     index: await orama.index.save(orama.data.index),
     docs: await orama.documentsStore.save(orama.data.docs),
     sorting: await orama.sorter.save(orama.data.sorting),
+    language: orama.tokenizer.language,
   }
 }
diff --git a/packages/orama/src/types.ts b/packages/orama/src/types.ts
index 0f557273e..601a3ebc2 100644
--- a/packages/orama/src/types.ts
+++ b/packages/orama/src/types.ts
@@ -1,4 +1,7 @@
+import { DocumentsStore } from './components/documents-store.js'
+import { Index } from './components/index.js'
 import { DocumentID, InternalDocumentID, InternalDocumentIDStore } from './components/internal-document-id-store.js'
+import { Sorter } from './components/sorter.js'
 import { Language } from './components/tokenizer/languages.js'
 
 export type Nullable<T> = T | null
@@ -113,10 +116,15 @@ export type Reduce<T, R = AnyDocument> = {
   getInitialValue: (elementCount: number) => T
 }
 
-export type GroupByParams<T> = {
-  properties: string[]
+// thanks to https://github.com/sindresorhus/type-fest/blob/main/source/literal-union.d.ts
+export type LiteralUnion<LiteralType, BaseType> = LiteralType | (BaseType & Record<never, never>) 
+
+export type SchemaValidKeys<T extends AnyOrama> = keyof T['schema'] extends string ? LiteralUnion<keyof T['schema'], string> : string;
+
+export type GroupByParams<T extends AnyOrama, ResultDocument> = {
+  properties: SchemaValidKeys<T>[]
   maxResult?: number
-  reduce?: Reduce<T>
+  reduce?: Reduce<ResultDocument>
 }
 
 export type ComparisonOperator = {
@@ -144,7 +152,7 @@ export type SorterParams<T extends AnyOrama> = {
   /**
    * The key of the document used to sort the result.
    */
-  property: keyof T['schema'] extends string ? keyof T['schema'] : string;
+  property: SchemaValidKeys<T>;
   /**
    * Whether to sort the result in ascending or descending order.
    */
@@ -269,7 +277,7 @@ export type SearchParams<T extends AnyOrama, ResultDocument = TypedDocument<T>>
    *  }
    * })
    */
-  groupBy?: GroupByParams<ResultDocument>
+  groupBy?: GroupByParams<T, ResultDocument>
 
   /**
    * Filter the search results.
@@ -289,7 +297,7 @@ export type SearchParams<T extends AnyOrama, ResultDocument = TypedDocument<T>>
    *  }
    * });
    */
-  where?: Record<string, boolean | string | string[] | ComparisonOperator>
+  where?: Partial<Record<SchemaValidKeys<T>, boolean | string | string[] | ComparisonOperator>>
 
   /**
    * Threshold to use for refining the search results.
@@ -805,7 +813,7 @@ export type PickInferGeneric<T, Default> = T extends AnyGeneric<infer Generic>
     : never
   : never
 
-export type Orama<TSchema, TIndex, TDocumentStore, TSorter> = FunctionComponents<TSchema> &
+export type Orama<TSchema, TIndex = Index, TDocumentStore = DocumentsStore, TSorter = Sorter> = FunctionComponents<TSchema> &
   Internals<TSchema, AnyGenericIndex<TIndex>, AnyGenericDocumentStore<TDocumentStore>, AnyGenericSorter<TSorter>> &
   ArrayCallbackComponents<any> &
   OramaID
diff --git a/packages/orama/tests/search.test.ts b/packages/orama/tests/search.test.ts
index bc5dbd938..533dfa4e2 100644
--- a/packages/orama/tests/search.test.ts
+++ b/packages/orama/tests/search.test.ts
@@ -1,6 +1,6 @@
 import t from 'tap'
 import { stopwords as englishStopwords } from '@orama/stopwords/english'
-import { Orama, create, getByID, insert, insertMultiple, search } from '../src/index.js'
+import { create, getByID, insert, insertMultiple, search } from '../src/index.js'
 
 t.test('search method', t => {
   t.test('with term', async t => {
@@ -584,7 +584,7 @@ t.test('search method', t => {
   t.end()
 })
 
-async function createSimpleDB(): Promise<[Orama, string, string, string, string]> {
+async function createSimpleDB() {
   let i = 0
   const db = await create({
     schema: {
@@ -641,5 +641,5 @@ async function createSimpleDB(): Promise<[Orama, string, string, string, string]
     },
   })
 
-  return [db, id1, id2, id3, id4]
+  return [db, id1, id2, id3, id4] as const
 }
diff --git a/packages/orama/tests/serialization.test.ts b/packages/orama/tests/serialization.test.ts
index 86b7167df..26e9ff8fb 100644
--- a/packages/orama/tests/serialization.test.ts
+++ b/packages/orama/tests/serialization.test.ts
@@ -1,14 +1,12 @@
 import t from 'tap'
-import { getInternalDocumentId } from '../src/components/internal-document-id-store.js'
-import type { Document } from '../src/types.js'
-import { Node as RadixNode } from '../src/trees/radix.js'
-import { create, insert, load, Result, save, search } from '../src/index.js'
-import { contains as trieContains } from '../src/trees/radix.js'
-import { Index } from '../src/components/index.js'
 import { DocumentsStore } from '../src/components/documents-store.js'
+import { Index } from '../src/components/index.js'
+import { getInternalDocumentId } from '../src/components/internal-document-id-store.js'
+import { create, insert, load, save, search } from '../src/index.js'
+import { Node as RadixNode, contains as trieContains } from '../src/trees/radix.js'
 
-function extractOriginalDoc(result: Result[]): Document[] {
-  return result.map(({ document }: Result) => document)
+function extractOriginalDoc(result) {
+  return result.map(({ document }) => document)
 }
 
 t.test('Edge getters', t => {
diff --git a/packages/orama/tests/sort.test.ts b/packages/orama/tests/sort.test.ts
index b04510233..74cadf4a5 100644
--- a/packages/orama/tests/sort.test.ts
+++ b/packages/orama/tests/sort.test.ts
@@ -1,5 +1,5 @@
 import t from 'tap'
-import { CustomSorterFunctionItem, create, insert, insertMultiple, load, remove, save, search } from '../src/index.js'
+import { create, insert, insertMultiple, load, remove, save, search } from '../src/index.js'
 
 t.test('search with sortBy', t => {
   t.test('on number', async t => {
@@ -388,9 +388,6 @@ t.test('search with sortBy', t => {
   })
 
   t.test('should allow custom function', async t => {
-    interface Doc {
-      string?: string
-    }
     const db = await create({
       schema: {
         string: 'string',
@@ -406,8 +403,8 @@ t.test('search with sortBy', t => {
     ])
 
     const result = await search(db, {
-      sortBy: (a: CustomSorterFunctionItem, b: CustomSorterFunctionItem) => {
-        return ((a[2] as unknown as Doc).string || '').localeCompare((b[2] as unknown as Doc).string || '')
+      sortBy: (a, b) => {
+        return (a[2].string || '').localeCompare(b[2].string || '')
       },
     })
 
diff --git a/packages/orama/tests/update.test.ts b/packages/orama/tests/update.test.ts
index 432a17560..3de124ac5 100644
--- a/packages/orama/tests/update.test.ts
+++ b/packages/orama/tests/update.test.ts
@@ -1,5 +1,5 @@
 import t from 'tap'
-import { create, insert, getByID, update, updateMultiple, count } from '../src/index.js'
+import { count, create, getByID, insert, update, updateMultiple } from '../src/index.js'
 
 t.test('update method', t => {
   t.plan(1)