JWT Decoder
Decode and inspect JSON Web Tokens. View header, payload, and verify structure — all in your browser.
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three Base64URL-encoded parts separated by dots: Header (algorithm and type), Payload (claims and data), and Signature (verification hash). JWTs are commonly used for authentication and API authorization.
Frequently Asked Questions
Is it safe to paste my JWT here?
Yes. Everything runs in your browser — no data is sent to any server.
Can this verify JWT signatures?
This tool decodes and displays JWT contents. For signature verification, you need the secret key or public key used to sign the token.
Does it show expiration time?
Yes. If the payload contains exp or iat claims, they are automatically converted to human-readable dates.