diff --git a/backend/src/klicktipp.ts b/backend/src/klicktipp.ts
new file mode 100644
index 000000000..3139cd296
--- /dev/null
+++ b/backend/src/klicktipp.ts
@@ -0,0 +1,28 @@
+import connection from '@/typeorm/connection'
+import { getKlickTippUser } from './apis/KlicktippController'
+import { User } from '../../database/entity/User'
+import { getConnection } from '@dbTools/typeorm'
+
+export async function retrieveNotRegisteredEmails(): Promise<string[]> {
+  const con = await connection()
+  if (!con) {
+    throw new Error('No connection to database')
+  }
+  const users = await User.find()
+  const notRegisteredUser = []
+  for (let i = 0; i < users.length; i++) {
+    const user = users[i]
+    try {
+      await getKlickTippUser(user.email)
+    } catch (err) {
+      notRegisteredUser.push(user.email)
+      // eslint-disable-next-line no-console
+      console.log(`${user.email}`)
+    }
+  }
+  await con.close()
+  console.log('User die nicht bei KlickTipp vorhanden sind: ', notRegisteredUser)
+  return notRegisteredUser
+}
+
+retrieveNotRegisteredEmails()