diff --git a/examples/audio_recorder/src/index.ts b/examples/audio_recorder/src/index.ts
index f92ff358ee..0bf1aea4c3 100644
--- a/examples/audio_recorder/src/index.ts
+++ b/examples/audio_recorder/src/index.ts
@@ -85,7 +85,7 @@ export default Canister({
     createRecording: update(
         [blob, text, principal],
         Result(Recording, AudioRecorderError),
-        (audio: blob, name: text, userId: Principal) => {
+        (audio, name, userId) => {
             const userOpt = users.get(userId);
 
             if (userOpt.length === 0) {
diff --git a/src/lib_functional/candid/index.ts b/src/lib_functional/candid/index.ts
index 868d6e968e..f5595f5723 100644
--- a/src/lib_functional/candid/index.ts
+++ b/src/lib_functional/candid/index.ts
@@ -42,12 +42,12 @@ import {
     AzleResult,
     Result,
     AzleTuple,
-    Tuple
+    AzleText
 } from '../../lib_new';
 
 export type TypeMapping<T> = T extends () => any
     ? ReturnType<T>
-    : T extends IDL.TextClass
+    : T extends AzleText
     ? string
     : T extends AzleBool
     ? bool
@@ -96,3 +96,7 @@ export type TypeMapping<T> = T extends () => any
     : T extends AzleEmpty
     ? empty
     : T;
+
+export type CandidType = {
+    _azleCandidType?: '_azleCandidType';
+};
diff --git a/src/lib_functional/candid/reference/record.ts b/src/lib_functional/candid/reference/record.ts
index d7e2b360cc..b6414687c3 100644
--- a/src/lib_functional/candid/reference/record.ts
+++ b/src/lib_functional/candid/reference/record.ts
@@ -1,11 +1,17 @@
-import { TypeMapping } from '..';
+import { CandidType, TypeMapping } from '..';
 import { IDL } from '@dfinity/candid';
 import { Parent, processMap } from '../../../lib_new/utils';
 import { v4 } from 'uuid';
 
-export function Record<T>(obj: T): {
+export function Record<
+    T extends {
+        [K in keyof T]: CandidType;
+    }
+>(
+    obj: T
+): {
     [K in keyof T]: TypeMapping<T[K]>;
-} {
+} & { _azleCandidType?: '_azleCandidType' } {
     const name = v4();
 
     return {
diff --git a/src/lib_functional/candid/reference/variant.ts b/src/lib_functional/candid/reference/variant.ts
index 2e99a9b700..bde604c04f 100644
--- a/src/lib_functional/candid/reference/variant.ts
+++ b/src/lib_functional/candid/reference/variant.ts
@@ -6,7 +6,7 @@ import { Null } from '../../../lib_new/primitives';
 
 export function Variant<T>(obj: T): RequireExactlyOne<{
     [K in keyof T]: TypeMapping<T[K]>;
-}> {
+}> & { _azleCandidType?: '_azleCandidType' } {
     const name = v4();
 
     return {
diff --git a/src/lib_functional/canister_methods/init.ts b/src/lib_functional/canister_methods/init.ts
index ee40c279bf..767caaa314 100644
--- a/src/lib_functional/canister_methods/init.ts
+++ b/src/lib_functional/canister_methods/init.ts
@@ -4,11 +4,11 @@ import {
     newTypesToStingArr
 } from '../../lib_new/method_decorators';
 import { Callback, CanisterMethodInfo, executeMethod } from '.';
-import { TypeMapping } from '../candid';
+import { CandidType, TypeMapping } from '../candid';
 import { Void } from '../../lib_new';
 
 export function init<
-    const Params extends ReadonlyArray<any>,
+    const Params extends ReadonlyArray<CandidType>,
     GenericCallback extends Callback<Params, Void>
 >(
     paramsIdls: Params,
diff --git a/src/lib_functional/canister_methods/post_upgrade.ts b/src/lib_functional/canister_methods/post_upgrade.ts
index 34a3ebe2c0..dd54c7a2a6 100644
--- a/src/lib_functional/canister_methods/post_upgrade.ts
+++ b/src/lib_functional/canister_methods/post_upgrade.ts
@@ -4,11 +4,11 @@ import {
     newTypesToStingArr
 } from '../../lib_new/method_decorators';
 import { Callback, CanisterMethodInfo, executeMethod } from '.';
-import { TypeMapping } from '../candid';
+import { CandidType, TypeMapping } from '../candid';
 import { Void } from '../../lib_new';
 
 export function postUpgrade<
-    const Params extends ReadonlyArray<any>,
+    const Params extends ReadonlyArray<CandidType>,
     GenericCallback extends Callback<Params, Void>
 >(
     paramsIdls: Params,
diff --git a/src/lib_functional/canister_methods/query.ts b/src/lib_functional/canister_methods/query.ts
index 99ca0338d5..b0802bbb9d 100644
--- a/src/lib_functional/canister_methods/query.ts
+++ b/src/lib_functional/canister_methods/query.ts
@@ -6,11 +6,11 @@ import {
     newTypesToStingArr
 } from '../../lib_new/method_decorators';
 import { Callback, CanisterMethodInfo, executeMethod } from '.';
-import { TypeMapping } from '../candid';
+import { CandidType, TypeMapping } from '../candid';
 
 export function query<
-    const Params extends ReadonlyArray<any>,
-    Return,
+    const Params extends ReadonlyArray<CandidType>,
+    Return extends CandidType,
     GenericCallback extends Callback<Params, Return>
 >(
     paramsIdls: Params,
diff --git a/src/lib_functional/canister_methods/update.ts b/src/lib_functional/canister_methods/update.ts
index 3f6f9e3c90..9e2046ec8c 100644
--- a/src/lib_functional/canister_methods/update.ts
+++ b/src/lib_functional/canister_methods/update.ts
@@ -6,11 +6,11 @@ import {
     newTypesToStingArr
 } from '../../lib_new/method_decorators';
 import { Callback, CanisterMethodInfo, executeMethod } from '.';
-import { TypeMapping } from '../candid';
+import { CandidType, TypeMapping } from '../candid';
 
 export function update<
-    const Params extends ReadonlyArray<any>,
-    Return,
+    const Params extends ReadonlyArray<CandidType>,
+    Return extends CandidType,
     GenericCallback extends Callback<Params, Return>
 >(
     paramsIdls: Params,
diff --git a/src/lib_new/primitives.ts b/src/lib_new/primitives.ts
index f9dcf8bcb0..ef93275ca7 100644
--- a/src/lib_new/primitives.ts
+++ b/src/lib_new/primitives.ts
@@ -3,6 +3,8 @@ import { CandidClass, Parent, toIDLType } from './utils';
 
 export class AzleNat {
     _kind: 'AzleNat' = 'AzleNat';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Nat;
     }
@@ -10,6 +12,8 @@ export class AzleNat {
 
 export class AzleNat64 {
     _kind: 'AzleNat64' = 'AzleNat64';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Nat64;
     }
@@ -17,6 +21,8 @@ export class AzleNat64 {
 
 export class AzleNat32 {
     _kind: 'AzleNat32' = 'AzleNat32';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Nat32;
     }
@@ -24,6 +30,8 @@ export class AzleNat32 {
 
 export class AzleNat16 {
     _kind: 'AzleNat16' = 'AzleNat16';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Nat16;
     }
@@ -31,6 +39,8 @@ export class AzleNat16 {
 
 export class AzleNat8 {
     _kind: 'AzleNat8' = 'AzleNat8';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Nat8;
     }
@@ -38,6 +48,8 @@ export class AzleNat8 {
 
 export class AzleInt {
     _kind: 'AzleInt' = 'AzleInt';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Int;
     }
@@ -45,6 +57,8 @@ export class AzleInt {
 
 export class AzleInt64 {
     _kind: 'AzleInt64' = 'AzleInt64';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Int64;
     }
@@ -52,6 +66,8 @@ export class AzleInt64 {
 
 export class AzleInt32 {
     _kind: 'AzleInt32' = 'AzleInt32';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Int32;
     }
@@ -59,6 +75,8 @@ export class AzleInt32 {
 
 export class AzleInt16 {
     _kind: 'AzleInt16' = 'AzleInt16';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Int16;
     }
@@ -66,6 +84,8 @@ export class AzleInt16 {
 
 export class AzleInt8 {
     _kind: 'AzleInt8' = 'AzleInt8';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Int8;
     }
@@ -73,6 +93,8 @@ export class AzleInt8 {
 
 export class AzleFloat64 {
     _kind: 'AzleFloat64' = 'AzleFloat64';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Float64;
     }
@@ -80,6 +102,8 @@ export class AzleFloat64 {
 
 export class AzleFloat32 {
     _kind: 'AzleFloat32' = 'AzleFloat32';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Float32;
     }
@@ -87,6 +111,8 @@ export class AzleFloat32 {
 
 export class AzleBlob {
     _kind: 'AzleBlob' = 'AzleBlob';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Vec(IDL.Nat8);
     }
@@ -94,6 +120,8 @@ export class AzleBlob {
 
 export class AzleNull {
     _kind: 'AzleNull' = 'AzleNull';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Null;
     }
@@ -101,6 +129,8 @@ export class AzleNull {
 
 export class AzleReserved {
     _kind: 'AzleReserved' = 'AzleReserved';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Reserved;
     }
@@ -108,6 +138,8 @@ export class AzleReserved {
 
 export class AzleEmpty {
     _kind: 'AzleEmpty' = 'AzleEmpty';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Empty;
     }
@@ -120,8 +152,19 @@ export class AzleBool {
     }
 }
 
+export class AzleText {
+    _kind: 'AzleText' = 'AzleText';
+    _azleCandidType?: '_azleCandidType';
+
+    static getIDL() {
+        return IDL.Text;
+    }
+}
+
 export class AzlePrincipal {
     _kind: 'AzlePrincipal' = 'AzlePrincipal';
+    _azleCandidType?: '_azleCandidType';
+
     static getIDL() {
         return IDL.Principal;
     }
@@ -157,7 +200,7 @@ export const Null: AzleNull = AzleNull as any;
 export type Null = null;
 export const reserved: AzleReserved = AzleReserved as any;
 export type reserved = any;
-export const text = IDL.Text;
+export const text: AzleText = AzleText as any;
 export type text = string;
 export const float32: AzleFloat32 = AzleFloat32 as any;
 export type float32 = number;
@@ -198,7 +241,10 @@ export class AzleOpt<T> {
     constructor(t: any) {
         this._azleType = t;
     }
+
     _azleType: CandidClass;
+    _azleCandidType?: '_azleCandidType';
+
     getIDL(parents: Parent[]) {
         return IDL.Opt(toIDLType(this._azleType, []));
     }
@@ -208,7 +254,10 @@ export class AzleVec<T> {
     constructor(t: any) {
         this._azleType = t;
     }
+
     _azleType: CandidClass;
+    _azleCandidType?: '_azleCandidType';
+
     getIDL(parents: Parent[]) {
         return IDL.Vec(toIDLType(this._azleType, []));
     }
@@ -218,7 +267,10 @@ export class AzleTuple<T extends any[]> {
     constructor(t: CandidClass[]) {
         this._azleTypes = t;
     }
+
     _azleTypes: CandidClass[];
+    _azleCandidType?: '_azleCandidType';
+
     getIDL(parents: Parent[]) {
         const candidTypes = this._azleTypes.map((value) => {
             return toIDLType(value, parents);
diff --git a/src/lib_new/result.ts b/src/lib_new/result.ts
index ecefbd1846..ac43d23bc4 100644
--- a/src/lib_new/result.ts
+++ b/src/lib_new/result.ts
@@ -1,6 +1,7 @@
 import { RequireExactlyOne } from '../lib/candid_types/variant';
+import { CandidType } from '../lib_functional';
 import { IDL } from './index';
-import { CandidClass, Parent, toIDLType } from './utils';
+import { Parent, toIDLType } from './utils';
 
 export class AzleResult<T, K> {
     constructor(ok: any, err: any) {
@@ -11,6 +12,8 @@ export class AzleResult<T, K> {
     _azleOk: any;
     _azleErr: any;
 
+    _azleCandidType?: '_azleCandidType';
+
     getIDL(parents: Parent[]) {
         return IDL.Variant({
             Ok: toIDLType(this._azleOk, parents),
@@ -19,7 +22,7 @@ export class AzleResult<T, K> {
     }
 }
 
-export function Result<Ok extends CandidClass, Err extends CandidClass>(
+export function Result<Ok extends CandidType, Err extends CandidType>(
     ok: Ok,
     err: Err
 ) {
diff --git a/src/lib_new/stable_b_tree_map.ts b/src/lib_new/stable_b_tree_map.ts
index eab2ef0b62..63489f2674 100644
--- a/src/lib_new/stable_b_tree_map.ts
+++ b/src/lib_new/stable_b_tree_map.ts
@@ -1,12 +1,11 @@
-import { TypeMapping } from '../lib_functional';
+import { CandidType, TypeMapping } from '../lib_functional';
 import { IDL, nat8, nat64, Opt } from './index';
 import { toIDLType } from './utils';
 
-export function StableBTreeMap<Key, Value>(
-    key: Key,
-    value: Value,
-    memoryId: nat8
-) {
+export function StableBTreeMap<
+    Key extends CandidType,
+    Value extends CandidType
+>(key: Key, value: Value, memoryId: nat8) {
     const keyIdl = toIDLType(key, []);
     const valueIdl = toIDLType(value, []);