Firebase function rejected because of missing appcheck token

[selcukbeyhan]

Related issues

[REQUIRED] Version info

"firebase-functions": "^3.24.1",

node:
"firebase-functions": "^3.24.1",

v22.15.0

14.2.2

[REQUIRED] Test case

[REQUIRED] Steps to reproduce

[REQUIRED] Expected behavior

[REQUIRED] Actual behavior

I have 1st gen callable functions.
When I call them, I receive following in the logs
2025-08-05 00:11:49.168 HKT
v2getXXXXXXX sjdugpudjdfb Failed to validate AppCheck token. FirebaseAppCheckError: Decoding App Check token failed. Make sure you passed the entire string JWT which represents the Firebase App Check token. at FirebaseAppCheckError.FirebaseError [as constructor] (/workspace/node_modules/firebase-admin/lib/utils/error.js:44:28) at FirebaseAppCheckError.PrefixedFirebaseError [as constructor] (/workspace/node_modules/firebase-admin/lib/utils/error.js:90:28) at new FirebaseAppCheckError (/workspace/node_modules/firebase-admin/lib/app-check/app-check-api-client-internal.js:187:28) at /workspace/node_modules/firebase-admin/lib/app-check/token-verifier.js:81:19 at process.processTicksAndRejections (node:internal/process/task_queues:95:5) { errorInfo: { code: 'app-check/invalid-argument', message: 'Decoding App Check token failed. Make sure you passed the entire string JWT which represents the Firebase App Check token.' }, codePrefix: 'app-check' }
2025-08-05 00:11:49.195 HKT
v2getXXXXXXX sjdugpudjdfb Callable request verification failed: AppCheck token was rejected.

I dont want to use AppCheck. It costs money.
Why is this happening? and how can I fix this?

Were you able to successfully deploy your functions?

YES

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[HassanBahati]

Hi @selcukbeyhan, thank you for opening this issue. We are going to look into it and we will keep you posted. Thank!

[selcukbeyhan]

We are using Flutter libraries of Firebase SDK.
We moved to a completely new project and published our functions. We still receive the same error.

Who triggers this appcheck requirement?
Does it come from the client side (mobile phone) or from the backend (functions)?

[HassanBahati]

Hi @selcukbeyhan, after an investigation into the issue you are facing; We recommend that you upgrade your firebase-functions version to the latest version. Kindly let us know if the issue persists. Thank you!