JWT Decoder
Decode JSON Web Tokens instantly. View the header, payload, and signature. Highlights expired tokens and displays timestamps in human-readable format.
How to Use the JWT Decoder
Paste a JSON Web Token into the input field. The decoder instantly splits it into its three parts — header, payload, and signature — and displays each section with human-readable labels. Time-based claims like exp, iat, and nbf are automatically converted to readable dates. Expired tokens are clearly flagged.
What Is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64-encoded parts separated by dots: a header (algorithm and token type), a payload (claims like user ID, roles, and expiration), and acryptographic signature. JWTs are widely used in OAuth 2.0, OpenID Connect, API authentication, and session management across web and mobile applications.
Common Use Cases
Debug authentication issues by inspecting token claims. Verify that token expiration times are set correctly. Check which permissions or roles are encoded in access tokens. Inspect the signing algorithm in the header — use our Hash Generator to compute HMAC signatures. Format the decoded payload with the JSON Formatter for easier reading. This tool decodes but does not verify signatures, as that requires the secret key. All decoding happens in your browser — your tokens are never sent to any server.