JWT Decoder: How to Read Token Payloads
JWTs (JSON Web Tokens) look intimidating — long strings of seemingly random characters separated by dots. But they're just encoded JSON. Once you know how to read them, debugging auth issues become...
Source: DEV Community
JWTs (JSON Web Tokens) look intimidating — long strings of seemingly random characters separated by dots. But they're just encoded JSON. Once you know how to read them, debugging auth issues becomes dramatically faster. This guide shows you exactly what's inside a JWT payload, how to decode and read it, and what to look for when auth is breaking. What Is a JWT? A JWT is a compact, signed token used to transmit information between parties. You'll find them in: OAuth 2.0 and OpenID Connect flows REST API authorization headers (Authorization: Bearer <token>) Session tokens in single-page applications Identity provider assertions (Auth0, Okta, Cognito, Firebase) A JWT looks like this: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c Three sections, separated by dots. Each section is Base64URL-encoded. The Three Parts of a JWT Part 1: Header The first section is the header. It de
