JWT Decoder

What is a JWT?

A JSON Web Token is a compact, signed token used for authentication and authorization. It has three parts separated by dots:

• Header — algorithm and token type
• Payload — claims like user ID, role, and expiration (exp)
• Signature — verifies the token wasn't tampered with

Security note: The payload is Base64-encoded, not encrypted — anyone can read it. Never put secrets in a JWT payload. This decoder only inspects tokens; it does not verify signatures.