JWT Decoder & Verifier
Decode the header and payload of your JWT and verify the signature locally in your browser.
Paste JWT Token
Decoded token content will be displayed here.
Guide & best practices
JWT Decoder with Claims Risk Analyzer
Analyze JWTs in a privacy-friendly way: header, payload, timestamps, algorithm hints and security risks.
Typical use cases
Ideal for OAuth/OIDC debugging, API integration, expiry issues, claim audits and JWT security education.
How Balou analyzes JWTs
The tool decodes header and payload locally, interprets time claims and flags risks such as alg=none, missing exp or long TTL.
JWT security best practices
Verify signatures server-side, reject unsafe algorithms, use short lifetimes and validate iss/aud/sub for your app.
Frequently asked questions
Does it verify the signature?
The decoder makes content readable and scores claims; signature verification belongs to dedicated verification flows.
Can I paste production tokens?
It runs locally, but production tokens should still be treated like secrets.
Why is missing exp risky?
Tokens without expiry may remain valid indefinitely if compromised.
Which tools complement it?
JWT Signer, Hash Generator and Secret Generator.