JWT Parser & Debugger
Decode, inspect, and parse JSON Web Tokens headers and payload claims in your browser with 100% privacy.
How JWT Parsing & Debugging Works & Technical Principles
Parse compact JWT strings into readable Header, Payload, and Signature components. Inspect auth claims and expiration dates with zero server transmission.
Technical Overview: Cryptographic Claims in Compact Token Notation
A JSON Web Token consists of three base64url-encoded parts delimited by dots: Header (specifying cryptographic algorithm and token type), Payload (containing claims like user ID, roles, and expiration time), and Signature (verifying token authenticity against tampering).
Input & Configuration
Paste an encoded JWT (such as an OAuth2 Bearer token or OpenID Connect ID token) into the input field.
Client-Side Processing
The parser splits the string by dot delimiters, converts base64url segments to UTF-8 strings, and formats JSON structures.
Instant Output & Export
View color-coded header algorithms, payload user claims, and human-readable expiration (exp) countdown statuses.
Key Capabilities & Features
Human-Readable Timestamp Formatting
Automatically converts standard epoch unix timestamps (exp, iat, nbf) into human-readable local dates and expiration states.
Color-Coded Token Dissection
Colorizes Header, Payload, and Signature segments to clarify token structure.
100% In-Browser Privacy Guarantee
Sensitive user claims, session IDs, and enterprise credentials are never transmitted over the network.
Formatted JSON Claims Viewer
Automatically indents and formats raw JSON payloads for effortless reading and debugging.
JSON Web Token (JWT) standard format specification
JSON Web Signature (JWS) cryptographic signature specification