JWT Decoder

About the JWT Decoder

JWT Decoder is a free online tool for developers who need to inspect JSON Web Tokens during OAuth flows, API debugging, or session troubleshooting. Paste a JWT — the long dot-separated string you get from an Authorization header or cookie — and the tool instantly splits it into its three parts: a header (algorithm and token type), a payload (claims like user ID, expiry, and roles), and a signature. The header and payload are decoded from Base64url and formatted as readable JSON. Expiry fields (exp, iat, nbf) are converted to human-readable timestamps so you can immediately see whether a token has expired without mentally converting Unix timestamps. The signature segment is displayed as raw Base64url — it cannot be decoded without the signing key, and this tool never asks for one. Your token is decoded server-side purely to pretty-print the JSON, and no token content is stored or logged.

Common use cases

• Inspect the claims inside an OAuth access token to debug a permissions or role issue.
• Check the exp claim to confirm whether a JWT has expired or is still valid.
• Identify the signing algorithm (HS256, RS256, etc.) and key ID (kid) from the header.
• Verify the iss and aud claims during an OIDC integration to ensure tokens are issued by the expected provider.
• Quickly read payload claims during API development without writing decode code.