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Notes on Firebase: Firestore, Authentication, security rules and the rest.

  1. Firebase App Check errors: fix 403s, “App attestation failed” and invalid tokens

    Every App Check error fails at one of two steps: getting a token or using it. How to tell which from the message, the debug token for emulators and localhost, the values that must match on Android, Apple and web, and AI Logic’s enforcement since November 2, 2026.

  2. Node.js 20 is decommissioned on Cloud Functions for Firebase: move to 24 or 22

    Since October 30, 2026, Firebase can’t deploy functions on Node.js 20. The one line to change, why 2nd gen goes to 24 and 1st gen to 22, the SDK versions to check, and what happens to functions you leave alone.

  3. Fix Google Sign-In error 10 and 28444 (Developer console is not set up correctly)

    ApiException 10 from the old Google Sign-In and [28444] from Credential Manager mean the same thing: the package name, the signing SHA-1 or the Web client ID doesn’t match your project. Which SHA-1 each build needs, what serverClientId takes, and what changed with Credential Manager.

  4. Firestore Enterprise vs Standard: start new apps on Enterprise

    Start new Firestore databases on the Enterprise edition: your code runs unchanged, indexed reads cost less, and the edition can’t be changed later. What you must handle yourself, and when Standard still wins.

  5. Firebase Remote Config pricing: what your app will pay

    Remote Config now charges per fetch above 100,000 a day. When the change reaches your project, what your app will pay, and the code that multiplies fetches.