diff --git a/backend/src/apis/KlicktippController.ts b/backend/src/apis/KlicktippController.ts
index 544b39d97..0777211ad 100644
--- a/backend/src/apis/KlicktippController.ts
+++ b/backend/src/apis/KlicktippController.ts
@@ -5,7 +5,7 @@ import CONFIG from '../config'
 
 const klicktippConnector = new KlicktippConnector()
 
-export const signIn = async (
+export const klicktippSignIn = async (
   email: string,
   language: string,
   firstName?: string,
diff --git a/backend/src/graphql/resolver/KlicktippResolver.ts b/backend/src/graphql/resolver/KlicktippResolver.ts
index fdffb940a..0ba2387e3 100644
--- a/backend/src/graphql/resolver/KlicktippResolver.ts
+++ b/backend/src/graphql/resolver/KlicktippResolver.ts
@@ -6,7 +6,7 @@ import {
   getKlickTippUser,
   getKlicktippTagMap,
   unsubscribe,
-  signIn,
+  klicktippSignIn,
 } from '../../apis/KlicktippController'
 import { RIGHTS } from '../../auth/RIGHTS'
 import SubscribeNewsletterArgs from '../arg/SubscribeNewsletterArgs'
@@ -36,6 +36,6 @@ export class KlicktippResolver {
   async subscribeNewsletter(
     @Args() { email, language }: SubscribeNewsletterArgs,
   ): Promise<boolean> {
-    return await signIn(email, language)
+    return await klicktippSignIn(email, language)
   }
 }
diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index 1f0bce30f..fb4e42bf6 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -13,6 +13,7 @@ import { LoginEmailOptIn } from '@entity/LoginEmailOptIn'
 import { User } from '@entity/User'
 import CONFIG from '../../config'
 import { sendAccountActivationEmail } from '../../mailer/sendAccountActivationEmail'
+import { klicktippSignIn } from '../../apis/KlicktippController'
 
 jest.mock('../../mailer/sendAccountActivationEmail', () => {
   return {
@@ -21,6 +22,13 @@ jest.mock('../../mailer/sendAccountActivationEmail', () => {
   }
 })
 
+jest.mock('../../apis/KlicktippController', () => {
+  return {
+    __esModule: true,
+    klicktippSignIn: jest.fn(),
+  }
+})
+
 let mutate: any
 let con: any
 
@@ -220,6 +228,101 @@ describe('UserResolver', () => {
       })
     })
   })
+
+  describe('setPassword', () => {
+    const createUserMutation = gql`
+      mutation (
+        $email: String!
+        $firstName: String!
+        $lastName: String!
+        $language: String!
+        $publisherId: Int
+      ) {
+        createUser(
+          email: $email
+          firstName: $firstName
+          lastName: $lastName
+          language: $language
+          publisherId: $publisherId
+        )
+      }
+    `
+
+    const createUserVariables = {
+      email: 'peter@lustig.de',
+      firstName: 'Peter',
+      lastName: 'Lustig',
+      language: 'de',
+      publisherId: 1234,
+    }
+
+    const setPasswordMutation = gql`
+      mutation ($code: String!, $password: String!) {
+        setPassword(code: $code, password: $password)
+      }
+    `
+
+    describe('valid optin code and valid password', () => {
+      let emailOptIn: string
+      let result: any
+      let loginUser: any
+      let newLoginUser: any
+      let newUser: any
+
+      beforeAll(async () => {
+        await mutate({ mutation: createUserMutation, variables: createUserVariables })
+        const loginEmailOptIn = await getRepository(LoginEmailOptIn)
+          .createQueryBuilder('login_email_optin')
+          .getMany()
+        loginUser = await getRepository(LoginUser).createQueryBuilder('login_user').getMany()
+        emailOptIn = loginEmailOptIn[0].verificationCode.toString()
+        result = await mutate({
+          mutation: setPasswordMutation,
+          variables: { code: emailOptIn, password: 'Aa12345_' },
+        })
+        newLoginUser = await getRepository(LoginUser).createQueryBuilder('login_user').getMany()
+        newUser = await getRepository(User).createQueryBuilder('state_user').getMany()
+      })
+
+      afterAll(async () => {
+        await resetDB()
+      })
+
+      it('updates the password', () => {
+        expect(newLoginUser[0].password).toEqual('3917921995996627700')
+      })
+
+      it('updates the public Key on both user tables', () => {
+        expect(newLoginUser[0].pubKey).toEqual(expect.any(Buffer))
+        expect(newLoginUser[0].pubKey).not.toEqual(loginUser[0].pubKey)
+        expect(newLoginUser[0].pubKey).toEqual(newUser[0].pubkey)
+      })
+
+      it('updates the private Key', () => {
+        expect(newLoginUser[0].privKey).toEqual(expect.any(Buffer))
+        expect(newLoginUser[0].privKey).not.toEqual(loginUser[0].privKey)
+      })
+
+      it('removes the optin', async () => {
+        await expect(
+          getRepository(LoginEmailOptIn).createQueryBuilder('login_email_optin').getMany(),
+        ).resolves.toHaveLength(0)
+      })
+
+      it('calls the klicktipp API', () => {
+        expect(klicktippSignIn).toBeCalledWith(
+          loginUser[0].email,
+          loginUser[0].language,
+          loginUser[0].firstName,
+          loginUser[0].lastName,
+        )
+      })
+
+      it('returns true', () => {
+        expect(result).toBeTruthy()
+      })
+    })
+  })
 })
 
 afterAll(async () => {
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index b751eb633..c17bb06e9 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -23,7 +23,7 @@ import { LoginEmailOptIn } from '@entity/LoginEmailOptIn'
 import { sendResetPasswordEmail } from '../../mailer/sendResetPasswordEmail'
 import { sendAccountActivationEmail } from '../../mailer/sendAccountActivationEmail'
 import { LoginElopageBuysRepository } from '../../typeorm/repository/LoginElopageBuys'
-import { signIn } from '../../apis/KlicktippController'
+import { klicktippSignIn } from '../../apis/KlicktippController'
 import { RIGHTS } from '../../auth/RIGHTS'
 import { ServerUserRepository } from '../../typeorm/repository/ServerUser'
 import { ROLE_ADMIN } from '../../auth/ROLES'
@@ -641,7 +641,12 @@ export class UserResolver {
     // TODO do we always signUp the user? How to handle things with old users?
     if (optInCode.emailOptInTypeId === EMAIL_OPT_IN_REGISTER) {
       try {
-        await signIn(loginUser.email, loginUser.language, loginUser.firstName, loginUser.lastName)
+        await klicktippSignIn(
+          loginUser.email,
+          loginUser.language,
+          loginUser.firstName,
+          loginUser.lastName,
+        )
       } catch {
         // TODO is this a problem?
         // eslint-disable-next-line no-console
diff --git a/backend/src/middleware/klicktippMiddleware.ts b/backend/src/middleware/klicktippMiddleware.ts
index 69a74480d..d0fde8195 100644
--- a/backend/src/middleware/klicktippMiddleware.ts
+++ b/backend/src/middleware/klicktippMiddleware.ts
@@ -1,5 +1,5 @@
 import { MiddlewareFn } from 'type-graphql'
-import { /* signIn, */ getKlickTippUser } from '../apis/KlicktippController'
+import { /* klicktippSignIn, */ getKlickTippUser } from '../apis/KlicktippController'
 import { KlickTipp } from '../graphql/model/KlickTipp'
 import CONFIG from '../config/index'
 
@@ -12,7 +12,7 @@ import CONFIG from '../config/index'
 //   // Do Something here before resolver is called
 //   const result = await next()
 //   // Do Something here after resolver is completed
-//   await signIn(result.email, result.language, result.firstName, result.lastName)
+//   await klicktippSignIn(result.email, result.language, result.firstName, result.lastName)
 //   return result
 // }