Firebase Messaging Test Sender

Firebase console → Project settings → Service accounts → Generate new private key. The file is read in your browser, signed with the Web Crypto API, and exchanged with Google for a one-hour token. It is never uploaded anywhere and never written to storage.

No key loaded

A service account key does not expire and can push to every user of the project. Use one scoped to a test project, give it only the Firebase Cloud Messaging API Service Agent role, and delete it in the console when you are done testing. Never load a production key here.