JWT Decoder

Decode and inspect JWT tokens with header, payload, and signature analysis.

About JSON Web Tokens

JSON Web Tokens (JWT) are an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. JWTs are widely used in authentication (OAuth 2.0, OpenID Connect), API authorization, and single sign-on (SSO). A JWT contains three Base64URL-encoded parts: the header specifies the signing algorithm, the payload carries claims (such as user ID, expiration time, and permissions), and the signature ensures the token has not been tampered with. This tool decodes all three parts entirely in your browser — no data leaves your device.

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Frequently Asked Questions

What is a JWT (JSON Web Token)?▾
A JWT is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three parts: a header (algorithm and token type), a payload (claims/data), and a signature for verification.
Can this tool verify JWT signatures?▾
This tool decodes and displays the JWT contents but does not verify signatures, as that requires the secret key or public key. It is designed for inspecting token structure and claims.
Is it safe to paste my JWT here?▾
Yes — all decoding happens entirely in your browser. No data is sent to any server. However, you should avoid sharing JWTs that contain sensitive information publicly.