JWT Decoder & Validator
Paste your JSON Web Token (JWT) to instantly decode its **Header** and **Payload** data.
When should you use this JWT Decoder & Validator?
- Inspect JWT header and payload contents instantly
- Debug authentication and authorization issues
- Verify token structure and expiration details
- When working with secure APIs and identity systems
Example use case:
You receive a JWT token from an authentication service and need to understand what data it contains. Paste the token into this tool to instantly decode the header and payload, inspect claims like issuer, expiration time, and user roles — all without sending the token to a server.
Tip: This tool decodes JWTs locally in your browser, so sensitive tokens never leave your device.
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JWT Decoder FAQ
It decodes a JWT token to show the header and payload (claims) in readable JSON for debugging.
No. Decoding only reads the token content. Validity requires signature verification using the correct secret or public key.
If decoding is client-side, it stays in your browser. Still avoid pasting sensitive production tokens when possible.
Common claims include exp (expiry), iat (issued at), iss (issuer), aud (audience), and user role/permissions fields.
JWT uses Base64URL encoding to make token parts URL-safe by replacing certain characters and removing padding.
The token may be expired based on the exp claim. Also confirm timezone and server clock if results look wrong.