Decode and inspect JSON Web Tokens (JWT) instantly. View header, payload, and verify token structure without sending data to any server.
A JSON Web Token (JWT, pronounced "jot") is an open standard (RFC 7519) for securely transmitting information between parties as a compact, URL-safe JSON object. JWTs are the backbone of modern authentication used by OAuth 2.0, OpenID Connect, and virtually every SaaS API.
Every JWT consists of three Base64-encoded sections separated by dots: Header (algorithm + token type), Payload (claims like user ID, role, expiration), and Signature (cryptographic proof that the token hasn't been tampered with). The header and payload are not encrypted anyone can decode them. The signature is what provides integrity.
Paste your token
Drop in a JWT from an API response, auth header, or cookie.
Inspect the parts
See the decoded header, payload, and signature in a readable format.
Check claims
Verify expiration (exp), issuer (iss), audience (aud), and custom claims.
Backend developers
Debug authentication issues by inspecting token claims and expiration.
Security engineers
Audit JWT payloads to ensure sensitive data isn't exposed in tokens.
Frontend developers
Decode access tokens to check user roles and permissions before rendering UI.
API testers
Verify that tokens contain the correct claims during integration testing.
A JSON Web Token (JWT) is a compact, URL-safe token format used for securely transmitting information between parties as a JSON object. It consists of three parts: header, payload, and signature.
Yes! All decoding happens entirely in your browser. No data is sent to any server. Your tokens remain private and secure.
This tool decodes and displays the JWT structure. Signature verification requires the secret key or public key, which is not handled client-side for security reasons.