🔑 JWT Decoder

Decode and inspect JWT tokens

JWT Token

About JWT Decoder

🚀 What is JWT?

JWT (JSON Web Token) is an open standard for securely transmitting information between parties as a JSON object. It's commonly used for authentication and information exchange in web applications.

✨ Key Features

Decode any JWT token instantly
View formatted header and payload
See token expiration time
Support for all JWT algorithms
100% client-side processing

JWT Structure

A JWT consists of three parts separated by dots (.)

                header.payload.signature
            

🔴 Header

Contains the algorithm (alg) and token type (typ). Example: {"alg":"HS256","typ":"JWT"}

🟢 Payload

Contains the claims/data. Common fields: sub, iat, exp, iss

🔵 Signature

Ensures token wasn't tampered with. Created using header, payload, and secret

Common JWT Claims

                    iss - Issuer
                

                    sub - Subject
                

                    aud - Audience
                

                    exp - Expiration
                

                    iat - Issued At
                

                    jti - JWT ID
                

Common Use Cases

🔐 Authentication

Verify user identity after login. Store user ID and permissions in the token.

🔄 API Authorization

Secure API endpoints by validating JWT tokens in request headers.

📊 Information Exchange

Safely transmit information between services with signed tokens.

⚠️ Security Note

JWT tokens are not encrypted - only encoded! Anyone can decode a JWT and read its contents. Never put sensitive information (passwords, SSNs) in a JWT payload. Use HTTPS to protect tokens in transit, and keep your signing secret secure.