JWT Decoder
Securely decode and inspect JSON Web Tokens (JWT). All processing happens locally in your browser.
What is a JWT Decoder?
A JWT Decoder is a tool that allows users to decode and inspect the contents of a JSON Web Token (JWT). JWTs are commonly used in web applications for secure authentication and data exchange between a client and a server. The decoder breaks the token into its three parts—header, payload, and signature—and converts the encoded data into a readable format. This helps developers understand the information stored inside the token, such as user details, permissions, and expiration time, without altering the token itself. JWT decoding is useful for debugging authentication flows and verifying how tokens are structured in systems that use standards defined by organizations like Internet Engineering Task Force.
How does JWT Decoder Work?
A JWT Decoder works by splitting a JSON Web Token (JWT) into its three main parts—header, payload, and signature—which are encoded using Base64URL. When a token is entered, the decoder separates these sections and converts the encoded header and payload into a human-readable JSON format. This allows users to view information such as the algorithm used, user data, permissions, and token expiration time. The decoder only reveals the contents of the token and does not modify or verify the signature unless additional verification is performed. JWTs follow a standard defined by the Internet Engineering Task Force and are widely used in modern authentication systems for secure data exchange.
