JWT decoder
Runs entirely in your browser. This decodes the token's contents — it does not verify the signature, so don't treat a decoded token as proof it's genuine.
What is JWT decoder?
A JSON Web Token (JWT) is a compact, three-part string used to carry claims between a client and server — a header, a payload of claims, and a signature — commonly used for API authentication and session tokens.
How to use it
Paste a JWT to see its decoded header and payload as readable JSON. This decodes the contents only — it does not verify the signature, so a decoded token is not proof it's genuine or untampered.
Example
A token's payload might decode to:
{"sub": "1234567890", "name": "Alex", "exp": 1735689600}