JWT Decoder
Decode and inspect JSON Web Tokens (JWTs). This tool helps you understand the structure and content of JWTs by breaking them down into their header, payload, and signature components.
Header
JSON
Payload
JSON
Signature
Base64URL
About JWT
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims between two parties. The claims in a JWT are encoded as a JSON object that is digitally signed using JSON Web Signature (JWS) and/or encrypted using JSON Web Encryption (JWE).
JWT Structure
A JWT consists of three parts separated by dots (.)
header.payload.signature
- Header: Contains metadata about the token
- Payload: Contains the claims (statements about an entity)
- Signature: Verifies the token's authenticity
Common JWT Claims
- iss (Issuer): Who issued the token
- sub (Subject): Who the token is about
- aud (Audience): Who the token is intended for
- exp (Expiration Time): When the token expires
- nbf (Not Before): When the token becomes valid
- iat (Issued At): When the token was issued
- jti (JWT ID): Unique identifier for the token
Best Practices
- Always use HTTPS for token transmission
- Set appropriate expiration times
- Include only necessary claims
- Use strong signing algorithms
- Validate tokens on the server side
- Store tokens securely
- Implement token refresh mechanisms
Common Use Cases
- Authentication in web applications
- API authorization
- Single Sign-On (SSO)
- Stateless session management
- Information exchange
- OAuth 2.0 and OpenID Connect
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