JWT Decoder

A JWT Decoder is a tool that takes a JSON Web Token (JWT) and decodes its header and payload sections into human-readable JSON. JWTs are used in authentication and authorization systems, and they consist of three parts: header, payload, and signature.

The header and payload are Base64URL-encoded JSON, which can be easily decoded to inspect the token's content, claims, and metadata.

Simply paste your JWT token into the decoder. The tool will instantly display the decoded header and payload as formatted JSON.

You can inspect claims like issuer (iss), subject (sub), audience (aud), expiration time (exp), and custom claims for debugging and analysis.

Developers often need to inspect JWTs during authentication and API development. This tool helps you quickly see what's inside a token without writing code or using external services.

It's useful for debugging OAuth, JWT-based authentication, single sign-on (SSO), and API access token issues.

The JWT header typically contains the algorithm used for signing (like HS256 or RS256) and the token type (JWT). This information helps the receiving application know how to verify the token's signature.

Our decoder displays the header in readable JSON so you can inspect the algorithm and other metadata.

The JWT payload contains the actual claims (statements) about the user or session. Standard claims include issuer (iss), subject (sub), audience (aud), expiration time (exp), and issued at (iat).

Applications can also include custom claims like user ID, roles, permissions, and any other data needed by the application.

Yes. All JWT decoding happens locally in your browser. Your token is never sent to a server, making this tool safe for sensitive authentication tokens.

For complete security, only use JWT decoders that process data locally. Our tool follows this principle to protect your tokens.