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Firebase domain not authorized to run this operation? Check authorized domains

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Source checked 10 Oct 2026 · Published 23 Oct 2026 · Last reviewed 23 Oct 2026 · By Ctrl+Z Therapy (how we test)

The short answer

Firebase's Auth FAQ says the error "This domain YOUR_REDIRECT_DOMAIN is not authorized to run this operation" is most likely caused because your redirect domain isn't listed as an authorized domain for Firebase Authentication, or the API key you use is invalid. Every host your web app runs on must be added: your custom domain and your preview address.

What to do

  1. In the Firebase console, go to Authentication, Settings, Authorized domains.
  2. Add every domain you deploy to, like your custom domain and your Vercel or Netlify address.
  3. Domain already listed? Check the API key your app uses.
  4. Ask your AI tool: "List every domain this app runs on (preview, live, custom domain). Tell me which ones must be added to Firebase Authentication's Authorized domains."

Good to know

  • In projects created after April 28, 2025, Firebase Authentication no longer includes localhost as an authorized domain by default. You can add it manually for development, but Google strongly discourages localhost in production projects.

Source

Checked on 10 Oct 2026. Prices, limits and settings change, so check the source before you rely on them.