JWT Decoder

What Is the JWT Decoder?

A JWT (JSON Web Token) decoder reads the Base64-encoded header and payload parts of a JWT and presents them as readable JSON. JWTs are used widely in authentication flows — OAuth2, OpenID Connect, API authorization — so the ability to quickly inspect their content is a core developer skill.

Debugging authentication issues, verifying claim values, checking token expiry, or inspecting API responses all require fast JWT inspection without needing to write a decoding script each time.

How to Use the JWT Decoder — Step by Step

1. 1

   Paste your JWT

   Copy the full token string (starts with eyJ...) from your auth header, response, or cookie.

2. 2

   Click Decode

   The tool splits the token into header, payload, and signature segments.

3. 3

   Review claims

   Inspect sub, iss, aud, exp, iat and all custom payload claims in a structured view.

4. 4

   Check expiry

   The tool flags whether the token is expired based on the 'exp' claim.

Frequently Asked Questions

Does this verify the JWT signature?

No. Signature verification requires the secret key or public certificate, which should never leave your server. This tool decodes the readable parts only.

Is my token sent to your server?

Your token is sent as a regular form POST for server-side decoding, then immediately discarded. No tokens are logged or stored.

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