JWT Decoder
Decode and inspect JSON Web Tokens instantly. View header, payload, and signature. Check expiry and standard claims with full privacy.
What is a JWT (JSON Web Token)?
A JWT is a compact, URL-safe token used for securely transmitting information between parties. It consists of three Base64URL-encoded parts separated by dots: the header (algorithm and token type), the payload (claims), and the signature (verification).
JWTs are widely used for authentication in modern web applications. The payload can contain standard claims like exp (expiration), iat (issued at), and sub (subject).
Privacy and Security
This JWT decoder processes your token entirely in your browser using JavaScript. Your token is never sent to any server - it never leaves your device. This makes it safe to decode tokens containing sensitive information.
Note: This tool decodes the token structure and displays the payload. It does not verify the signature - for signature verification you need the secret key.