Your backend verifies Firebase ID tokens. You want to call it from curl or Postman as a specific user. Firebase gives you no button for that. The usual answers are a sign-in REST call with an email and password (only works for password users), the Auth emulator (not your real project), or a small Admin SDK script that creates a custom token and exchanges it. I wrote that script one too many times, so I turned it into a desktop app. What the flow actually is Getting an ID to...