JWT Decoder
Decode a JSON Web Token (JWT) and inspect its header and payload — free, instant, and nothing is sent to a server.
Header
Payload
Signature
The signature cannot be verified without the secret key. This tool only decodes the header and payload.
JWT Decoder Online
Paste a JSON Web Token into the field above and click Decode JWT to instantly inspect its header and payload. Everything runs in your browser — your token is never sent to a server.
What Is a JWT?
A JSON Web Token is a compact, URL-safe string used to represent claims between two parties. It consists of three Base64URL-encoded parts separated by dots: a header (algorithm and token type), a payload (claims such as user ID and expiry), and a signature (used to verify the token hasn't been tampered with).
Common Uses
- Debugging authentication tokens returned by an API or identity provider
- Checking the expiry (
exp) or issued-at (iat) claims - Inspecting custom claims embedded in a token during development
Security Note
Never paste production tokens containing sensitive data into online tools you don't control. This tool processes everything locally in your browser, but you should still treat JWTs as secrets.