JWT Decoder

What is a JWT?

JSON Web Tokens are an open standard for securely transmitting information between parties as a JSON object. Commonly used for authentication and authorization in web applications.

JWT Structure

A JWT has three parts: header.payload.signature

• Header: Token type and signing algorithm
• Payload: Claims (user data, expiration, issuer)
• Signature: Cryptographic signature to verify integrity

Security Note

This tool decodes JWTs but does NOT verify signatures. JWT payloads are Base64-encoded, not encrypted — anyone can read them. Never put production secrets into online tools.