A JSON Web Token (JWT) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. It consists of three Base64URL-encoded parts: a Header (algorithm), a Payload (claims/data), and a Signature (verification).

How do I decode a JWT?

Paste your JWT token into the input field. GoodParse splits the token by dots, Base64URL-decodes the Header and Payload sections, and displays them as formatted JSON. The Signature is not verified — it is shown raw.

Is it safe to paste my JWT here?

Yes. All decoding happens locally in your browser. Your token is never sent to any server. However, avoid sharing your JWT in public places, as anyone with the token can impersonate the user it represents until it expires.

What is the exp claim in a JWT?

The exp (expiration time) claim is a Unix timestamp that indicates when the JWT expires and is no longer valid. GoodParse automatically converts exp and iat (issued at) timestamps to human-readable local dates.

What is the difference between JWT and an API key?

An API key is an opaque string with no built-in expiration or user data. A JWT is self-contained — it carries claims (user ID, roles, permissions) and has a built-in expiration time. JWTs are verified by checking the signature, while API keys require a database lookup.

ToolsJWT Debugger & Inspector

JWT Debugger & Inspector

Inspect claims, decode base64Url header/payload structures, and validate JSON Web Token expiration dates instantly.

Encoded TokenEmpty

Decoded HeaderWaiting

Decoded Payload (Claims)Waiting

How to use JWT Debugger & Inspector?

1
Paste your raw JSON Web Token (JWT) in the left panel input area.
2
The decoder splits the base64Url components: header (red), payload (purple), signature (blue).
3
View the claims structure formatted neatly in JSON on the right.
4
Check expiration dates automatically parsed from the 'exp' claim.

Frequently Asked Questions

What is a JWT?

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.

Is it safe to decode my JWT here?

Yes. Our decoder runs completely locally in your browser. Your token is never sent to our servers, keeping your sensitive claims secure.

Decoding JSON Web Tokens (JWT) Securely

Quick Answer: A JSON Web Token (JWT) is a standardized, stateless authentication token consisting of three Base64Url-encoded parts: a header, a payload containing user claims, and a cryptographic signature.

JSON Web Tokens (JWT) have become the industry standard for stateless authentication in modern single-page applications (SPAs) and REST APIs. A JWT consists of three parts: a Header (algorithm info), a Payload (claims/data), and a Signature (security verification). While they appear as random strings of characters, they are simply Base64Url encoded JSON objects.

Our JWT Decoder allows you to instantly unpack and read the contents of any JSON Web Token. By pasting your token into the tool, you can immediately inspect the Header and Payload sections to verify user roles, expiration times (exp), and issued-at timestamps (iat).

Why Use a Local JWT Decoder?

Security First: JWTs often contain sensitive user data like email addresses, IDs, and session states. Using an online decoder that uploads your token to a backend server is incredibly risky. GoodParse performs all decoding locally in your browser, guaranteeing zero data leakage.
Timestamp Conversion: JWTs store dates as Unix timestamps (seconds since epoch). Our tool automatically detects standard claims like exp and translates them into human-readable local times, making debugging much easier.
Color-Coded Syntax: Visualizing the token structure with clear syntax highlighting helps you quickly identify formatting errors or missing claims during development.

JWT vs API Key vs Session Token: Authentication Comparison

Choosing the right authentication mechanism is critical for application security. Here is how JWT compares to other methods:

Feature	JWT (Stateless)	Session Cookies (Stateful)	API Keys
State Management	Stateless (Self-contained)	Stateful (Stored in DB)	Stateless (Server validates)
Data Storage	Contains user claims & roles	Only contains session ID reference	Usually no user data, just auth
Revocation	Hard (Requires blocklist)	Easy (Delete session from DB)	Easy (Revoke key)
XSS Vulnerability	High (if stored in LocalStorage)	Low (if HttpOnly Cookie)	Medium
Primary Use Case	Microservices, SPAs, OIDC	Traditional monolithic web apps	Server-to-Server API access

Whether you are debugging authentication issues in a React app, or verifying a token issued by Auth0 or AWS Cognito, our local JWT Decoder is the safest and fastest way to inspect your tokens.