Decode, inspect, and verify JSON Web Tokens (JWT) in real-time. 100% client-side parsing ensures your authentication secrets never leave your browser.
// Header JSON will appear here...// Decoded claims JSON will appear here...Your authentication tokens, user payloads, and secret keys are decoded entirely in your web browser. No token data is ever transmitted to a backend server.
Stop manually converting UNIX epoch timestamps. Our decoder parses standard JWT claims like exp, iat, and nbf into localized date strings.
Test HMAC SHA-256 signatures directly in browser using native Web Crypto APIs to confirm token integrity and detect secret mismatches instantly.
Visual color separation for JWT parts (Header in red/pink, Payload in blue/purple, Signature in teal) allows you to inspect token composition at a glance.
A JSON Web Token (JWT) is a compact, URL-safe standard (RFC 7519) for transmitting claims securely between two parties. It is widely used for user authentication, SSO (Single Sign-On), and web API access authorization.
Yes! DevSuite processes all JWT strings locally within your web browser using vanilla JavaScript. We do not store, log, or transmit tokens to any remote API or server.
A JWT consists of three base64url-encoded strings separated by dots (.):
Signature verification recalculates the hash of the Header and Payload using the specified secret key and compares it against the signature provided in the token. If they match, the token is verified and untampered.