Decode and inspect JSON Web Tokens securely in your browser.
A JSON Web Token (JWT) Decoder is a crucial utility for backend developers and security engineers. It allows you to decode the Base64Url encoded segments of a JWT to inspect its header and payload claims. This is essential when verifying user authentication tokens, debugging API authorization issues, or checking token expiration times.
Paste your JWT string (typically three Base64 encoded strings separated by dots) into the input area. The tool instantly splits the token and decodes the header and payload into readable JSON formats. You can quickly see the algorithm used, the issuer, the subject, and any custom claims included in the token. The signature verification part is omitted here since decoding does not require the secret key.
JWTs often contain sensitive user information or internal system IDs. Pasting them into third-party online decoders can expose your system to security risks. Our JWT Decoder operates completely locally in your browser, ensuring that your tokens are never transmitted across the internet or stored on external servers.
No, this tool only decodes the header and payload for inspection. It does not verify the signature since it does not ask for your secret key.
Yes, the decoding process happens 100% locally in your browser. We never send your token to any server.
The payload is presented as formatted, easy-to-read JSON, showing all standard and custom claims.