JWT Decoder
Paste a JWT and see the header, payload, expiry, and signature parts decoded. Everything happens in your browser.
Header (Algorithm & Key ID)
Payload (Claims & Expiration)
No keys parsed yet.
How to use JWT Decoder
- Paste a JWT token.
- Read the decoded header and payload.
- Check the expiry hint.
What is JWT Decoder?
JWTs are three Base64URL-encoded parts separated by dots: header.payload.signature. This tool decodes the first two and shows the third, plus computes expiry from iat and exp claims. The signature is NOT verified — that requires the issuer's secret or public key.
FAQ
- Why isn't the signature verified?
- Verification requires the signing key, which we don't have. Use your server's secret or the JWKS endpoint to verify trust.
- Is my JWT secure to paste here?
- Tokens can grant access — only paste tokens you're OK seeing, or test tokens. Nothing leaves your browser, but be cautious.
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