diff --git a/backend/src/graphql/model/CheckUsernameResponse.ts b/backend/src/graphql/model/CheckUsernameResponse.ts
deleted file mode 100644
index fe93511bc..000000000
--- a/backend/src/graphql/model/CheckUsernameResponse.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-/* eslint-disable @typescript-eslint/no-explicit-any */
-/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
-import { ObjectType, Field } from 'type-graphql'
-
-@ObjectType()
-export class CheckUsernameResponse {
-  constructor(json: any) {
-    this.state = json.state
-  }
-
-  @Field(() => String)
-  state: string
-}
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index d4746589b..ab49ee6bf 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -3,8 +3,8 @@
 
 import { Resolver, Query, Args, Arg, Authorized, Ctx, UseMiddleware, Mutation } from 'type-graphql'
 import { from_hex as fromHex } from 'libsodium-wrappers'
+import { getCustomRepository } from 'typeorm'
 import CONFIG from '../../config'
-import { CheckUsernameResponse } from '../model/CheckUsernameResponse'
 import { LoginViaVerificationCode } from '../model/LoginViaVerificationCode'
 import { SendPasswordResetEmailResponse } from '../model/SendPasswordResetEmailResponse'
 import { UpdateUserInfosResponse } from '../model/UpdateUserInfosResponse'
@@ -22,7 +22,6 @@ import {
   klicktippNewsletterStateMiddleware,
 } from '../../middleware/klicktippMiddleware'
 import { CheckEmailResponse } from '../model/CheckEmailResponse'
-import { getCustomRepository } from 'typeorm'
 import { UserSettingRepository } from '../../typeorm/repository/UserSettingRepository'
 import { Setting } from '../enum/Setting'
 import { UserRepository } from '../../typeorm/repository/User'
@@ -276,8 +275,8 @@ export class UserResolver {
     return response
   }
 
-  @Query(() => CheckUsernameResponse)
-  async checkUsername(@Args() { username }: CheckUsernameArgs): Promise<CheckUsernameResponse> {
+  @Query(() => Boolean)
+  async checkUsername(@Args() { username }: CheckUsernameArgs): Promise<Boolean> {
     // Username empty?
     if (username === '') {
       throw new Error('Username must be set.')
@@ -296,7 +295,7 @@ export class UserResolver {
       throw new Error(`Username "${username}" already taken.`)
     }
 
-    return new CheckUsernameResponse({ state: 'success' })
+    return true
   }
 
   @Query(() => CheckEmailResponse)
diff --git a/frontend/src/graphql/queries.js b/frontend/src/graphql/queries.js
index 2ee381dd8..01021f601 100644
--- a/frontend/src/graphql/queries.js
+++ b/frontend/src/graphql/queries.js
@@ -75,9 +75,7 @@ export const sendResetPasswordEmail = gql`
 
 export const checkUsername = gql`
   query($username: String!) {
-    checkUsername(username: $username) {
-      state
-    }
+    checkUsername(username: $username)
   }
 `
 
diff --git a/frontend/src/validation-rules.js b/frontend/src/validation-rules.js
index 5552794d1..54f4c3090 100644
--- a/frontend/src/validation-rules.js
+++ b/frontend/src/validation-rules.js
@@ -59,7 +59,7 @@ export const loadAllRules = (i18nCallback) => {
           },
         })
         .then((result) => {
-          return result.data.checkUsername.state === 'success'
+          return result.data.checkUsername
         })
         .catch(() => {
           return false