Decode a Firebase ID Token
Decode a Firebase Authentication ID token to inspect uid, email, auth_time and sign-in provider claims. Free browser-based Firebase JWT decoder.
Part of the free JWT Decoder. Runs in your browser — nothing is uploaded.
Decode a Firebase ID Token
Firebase ID tokens are RS256 JWTs issued by securetoken.google.com/<project-id>. Their payload contains the user ID, sign-in provider and timestamps. Decode one to debug why your backend rejects a request.
Worked example: Illustrative Firebase-style ID token
JWT
eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImtleS0yMDI2LTAxIn0.eyJpc3MiOiJodHRwczovL3NlY3VyZXRva2VuLmdvb2dsZS5jb20vbXktcHJvamVjdCIsImF1ZCI6Im15LXByb2plY3QiLCJhdXRoX3RpbWUiOjE3NjcyMjU2MDAsInVzZXJfaWQiOiJhYmMxMjNYWVoiLCJzdWIiOiJhYmMxMjNYWVoiLCJpYXQiOjE3NjcyMjU2MDAsImV4cCI6MTc2NzIyOTIwMCwiZW1haWwiOiJhZGFAZXhhbXBsZS5jb20iLCJlbWFpbF92ZXJpZmllZCI6dHJ1ZSwiZmlyZWJhc2UiOnsic2lnbl9pbl9wcm92aWRlciI6InBhc3N3b3JkIn19.c2lnbmF0dXJl
Decoded token
// HEADER
{
"alg": "RS256",
"typ": "JWT",
"kid": "key-2026-01"
}
// PAYLOAD
{
"iss": "https://securetoken.google.com/my-project",
"aud": "my-project",
"auth_time": 1767225600,
"user_id": "abc123XYZ",
"sub": "abc123XYZ",
"iat": 1767225600,
"exp": 1767229200,
"email": "ada@example.com",
"email_verified": true,
"firebase": {
"sign_in_provider": "password"
}
}
// CLAIM TIMES (UTC)
iat: 2026-01-01 00:00:00 UTC
exp: 2026-01-01 01:00:00 UTCPractical tip
Firebase ID tokens last one hour. Call getIdToken() on the client, which refreshes automatically, instead of storing the token yourself.
How to use this JWT Decoder
- 1Use the live tool above — it runs entirely in your browser and never uploads your data.
- 2Paste the sample from the worked example, or use your own input.
- 3Copy the result, then adapt the same steps in your editor, script, or pipeline.
Decode a Firebase ID Token FAQs
How do I verify a Firebase ID token on my server?
Use the Firebase Admin SDK verifyIdToken method. It checks the signature, issuer, audience and expiry for you.
What should the aud claim equal?
For Firebase ID tokens, aud must equal your Firebase project ID, and iss must be https://securetoken.google.com/<project-id>.
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