π JWT Decoder
Inspect, decode, and validate JSON Web Tokens β client-side, no data leaves your browser
How to Use JWT Decoder
Decode, inspect, and validate JSON Web Tokens β complete developer guide
β‘ Decode JWTs in 3 Simple Steps
Paste Your JWT
Copy any JSON Web Token from your browser, API response, or authentication flow and paste it into the input field.
Decode Automatically
The decoder instantly parses your token β no button needed. View the Header (algorithm, type) and Payload (claims, user data).
Inspect & Copy
Copy header, payload, signature, or the full token. View token statistics like length, size, and algorithm used.
JWT (JSON Web Token) is an open standard for securely transmitting information between parties. JWTs are commonly used for authentication, API authorization, and single sign-on (SSO).
Key features include: instant decoding of header and payload, signature validation detection, token statistics (length, size, algorithm), and 100% client-side processing. Perfect for debugging OAuth flows, testing API tokens, and understanding JWT structure.
Our free JWT decoder tool works entirely in your browser β no data is ever sent to any server. Your tokens stay private and secure.
β Everything You Need to Know About JWTs
JWT (JSON Web Token) is a compact, URL-safe token format used for authentication and authorization. It's commonly used in OAuth2, OpenID Connect, REST APIs, and single sign-on systems. A JWT consists of three parts: Header, Payload, and Signature.
The Header contains metadata like the signing algorithm (HS256, RS256) and token type. The Payload contains claims β user ID, email, roles, expiration time, and custom data. The Signature verifies the token hasn't been tampered with.
100% safe! Our JWT decoder works entirely in your browser using JavaScript. No token data is ever sent to any server β everything stays on your device. Perfect for debugging production tokens with sensitive user information.
The tool detects the algorithm type and shows whether the token uses symmetric (HS256) or asymmetric (RS256/ES256) signing. It also displays the signature for inspection. Full signature validation requires the secret key or public certificate.
Token length shows total characters. Header/Payload size shows base64-decoded bytes. Algorithm shows the signing algorithm used. These stats help understand token size for API limits and debugging.
100% free β no signup required! No hidden fees, no premium tiers, no watermarks. Decode unlimited JWTs. We believe essential developer tools should be accessible to everyone.