JWT Decoder Online
Decode JSON Web Tokens (JWT) locally. View header and payload data without sending tokens to any server.
▶About JWT Decoder
A JSON Web Token (JWT) is a compact, URL-safe token format defined in RFC 7519 for securely transmitting claims between two parties. A JWT consists of three Base64-encoded parts — header, payload, and signature — separated by dots.
This free online JWT decoder lets you inspect any JWT instantly. Paste a token to view the algorithm, issuer, expiration, custom claims, and other metadata from the header and payload. All decoding happens client-side — your tokens are never sent to any server.
Common use cases: debugging OAuth 2.0 and OpenID Connect flows, verifying token expiration (exp) and issued-at (iat) claims, inspecting custom claims in API authentication tokens, and troubleshooting SSO and identity provider integrations.
▶Frequently Asked Questions
▶What is a JSON Web Token (JWT)?
A JWT is a compact, URL-safe token format defined in RFC 7519. It consists of three Base64url-encoded parts separated by dots: a header (algorithm and type), a payload (claims), and a signature.
▶Is it safe to decode JWT tokens online?
Yes, when using a client-side decoder like this one. All decoding happens in your browser — the token is never uploaded to any server.
▶Can this tool verify JWT signatures?
This tool decodes and displays the JWT header and payload. Signature verification requires the signing secret or public key, which this client-side tool does not perform to avoid exposing your keys.
▶How do I check if a JWT is expired?
After decoding, look at the 'exp' (expiration) claim in the payload. It is a Unix timestamp. Compare it with the current time — if 'exp' is in the past, the token has expired.