JWT Decoder

JWT Decoder

JSON Web Tokens (JWT) are a compact, URL-safe format for transmitting signed claims between services — widely used in authentication headers, OAuth 2.0 flows, and session management. A JWT consists of three Base64URL-encoded parts separated by dots: the header (algorithm and token type), the payload (claims such as user ID, roles, and expiry), and the signature. This decoder splits any JWT and shows each part in readable JSON, along with the expiry time and whether the token has already expired. Note that this tool decodes only — it does not verify the signature cryptographically, so it is intended for inspection and debugging, not security validation.