Developer Reference
JWT Structure & Claims
Anatomy of a JSON Web Token. Header, Payload, Signature, and standard claims.
JSON Web Tokens (JWT) are an open, industry standard RFC 7519 method for representing claims securely between two parties. Understanding their structure is key to securing your APIs.
Structure
Structure
Algorithm & Token Type (Base64Url encoded)
Structure
Data/Claims (sub, name, iat) (Base64Url encoded)
Security
Security
HMACSHA256(base64UrlEncode(header) + "." + base64UrlEncode(payload), secret)
Usage
Usage
Standard Authorization header prefix ("Bearer <token>")
Claims
Claims
Issuer
Claims
Subject (User ID)
Claims
Expiration Time
Claims
Issued At
This reference breaks down the three parts of a JWT and explains standard claims like 'iss' (issuer), 'exp' (expiration), and 'sub' (subject).