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JWT & Bearer Token Inspector - Decode JSON Web Tokens

Free online JWT decoder and Bearer token inspector. Decode JWT headers, payloads, and check expiration claims instantly in your browser.

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Use JWT & Bearer Token Inspector - Decode JSON Web Tokens while building with AI coding assistants, agents, and LLM workflows: validate generated output, transform payloads, debug integrations, and prepare reliable inputs without leaving your browser.

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What Is a JWT Bearer Token Inspector?

A JWT (JSON Web Token) Bearer Token Inspector is a tool that decodes and displays the contents of JWT tokens used in web authentication. JWTs consist of three Base64URL-encoded parts: a header specifying the algorithm, a payload containing claims like user identity and expiration, and a signature for verification. This tool parses the header and payload so you can inspect claims such as exp, iat, sub, and iss without needing a backend or library. It also accepts the full 'Bearer' authorization header format for convenience.

How to Use the JWT Inspector

  1. Paste your JWT token into the input field. You can include the 'Bearer ' prefix — it will be stripped automatically.
  2. The tool instantly decodes and displays the header (algorithm, token type) and payload (claims) as formatted JSON.
  3. Check the timestamp claims: iat (issued at), exp (expiration), and nbf (not before) are converted to human-readable dates.
  4. If the token is expired, a red warning banner appears with the exact expiration time.
  5. Use the copy buttons to copy the decoded header or payload JSON for use in debugging or documentation.

Common Use Cases

  • API Debugging — Quickly inspect access tokens returned by OAuth2 flows to verify claims, scopes, and expiration before making API calls.
  • Authentication Troubleshooting — When users report auth failures, decode their JWT to check if it's expired, issued by the wrong provider, or missing required claims.
  • Security Auditing — Review token contents to ensure sensitive data isn't exposed in the payload and that proper algorithms are specified in the header.
  • Development & Testing — During development, verify that your identity provider issues tokens with the correct structure, claims, and audience values.

FAQ

Does this tool verify the JWT signature?
No. This tool decodes and displays the header and payload but does not verify the signature. Signature verification requires the signing key, which should remain on your server. This tool is designed for inspecting token contents, not for validating authenticity.
Is it safe to paste my JWT token here?
Yes. All processing happens entirely in your browser using JavaScript. No data is sent to any server. However, you should still avoid sharing production tokens with elevated privileges in any tool — treat tokens like passwords.
What does 'Bearer' mean in an Authorization header?
Bearer is an HTTP authentication scheme defined in RFC 6750. It means the client is presenting a token (the 'bearer token') to access a protected resource. The format is 'Authorization: Bearer 'token'' where the token is typically a JWT.
Why does my token show as expired?
The tool compares the 'exp' (expiration) claim in the token payload against your current local time. If the expiration timestamp is in the past, the token is marked as expired. Note that clock skew between your machine and the issuing server can sometimes cause false positives.

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