JWT Decoder
Inspect the header and payload of any JWT without sending it to a server.
Inspect the header and payload of any JWT without sending it to a server.
How to use JWT Decoder
- 1
Paste your JSON Web Token string into the input area.
- 2
The tool immediately splits the token into its three parts — header, payload, and signature.
- 3
Review the decoded header to see the algorithm and token type.
- 4
Review the decoded payload to inspect claims like expiration time (exp), issuer (iss), and custom data.
- 5
Check the expiration status indicator to see if the token is still valid.
Real examples of JWT Decoder in action
eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2MDAwMDAwMDB9.xyz
Header: HS256, Payload: {exp: 1600000000}, Status: EXPIRED (expired Sep 2020)A freshly issued API token string
Payload shows sub, iat, exp, and custom roles: ['admin', 'billing']
A token from a 3rd-party identity provider
iss: https://auth.example.com/, aud: api.example.com (confirms expected issuer)
Who is JWT Decoder for?
Authentication engineers debugging expired or malformed JWTs in production
API integrators inspecting third-party OAuth tokens during onboarding
Security reviewers auditing claims, scopes, and token expiry
Frontend developers checking what user roles a session token contains
Support engineers diagnosing 401 Unauthorized errors reported by users
Why use JWT Decoder?
- Instantly decodes the header and payload without needing the signing key.
- Highlights expiration status so you can quickly tell if a token has expired.
- Everything runs in your browser — sensitive tokens are never sent to a server.
- Displays claims in formatted, readable JSON for easy inspection.
Common use cases
- Debug authentication issues by inspecting the claims and expiration of a JWT returned by your API.
- Verify that a JWT contains the expected scopes, roles, or custom claims before deploying a change.
- Check when a token expires without writing code to parse it manually.
- Inspect third-party JWTs during API integration to understand the data structure they provide.
How JWT Decoder keeps your data private
Decoding splits the JWT on dots and runs atob() directly in your browser — the token string never touches a network. This is essential because a JWT represents an active session: if it leaked through a server-side tool, an attacker could replay it. Paste production tokens here without risk; nothing is logged or transmitted.
How JWT Decoder compares to alternatives
Honest comparison to other popular options — pick the right tool for the job.
| Tool | Main limitation |
|---|---|
| JWT.io | Despite being reputable, pastes tokens into a live web form, which is risky for production tokens |
| Postman | Requires opening Postman and navigating through settings to decode a single token |
| Custom curl + base64 command | Requires chaining shell commands every time, error-prone under pressure |
| JWT Decoder | Free, runs in your browser, no sign-up, no watermarks, no file-size limits beyond your device memory. |
About JWT Decoder
JSON Web Tokens are the backbone of modern authentication, but their Base64-encoded format makes them impossible to read without a tool. Xevon Tools' JWT Decoder splits any JWT into its three parts — header, payload, and signature — and displays the decoded JSON in a clean, formatted view. You can inspect the algorithm, issuer, subject, expiration time, scopes, roles, and any custom claims the token carries. An expiration status indicator tells you at a glance whether the token is still valid. Because the decoding runs entirely in your browser, there is no risk of leaking sensitive tokens to a server — a critical concern when working with production credentials. This tool is invaluable during API development, authentication debugging, and third-party integration work. Note that it does not verify signatures (that requires the signing key), but for inspecting claims and diagnosing auth issues, it provides everything you need in seconds.
Frequently asked questions
Helpful tutorials
Practical guides that show real workflows for this tool and related tasks.
Your files never leave your device
Every tool on Xevon Tools runs 100% in your browser. No uploads, no servers, no tracking. Free forever.
Embed JWT Decoder on your site
Add this tool to your own website, blog, or internal tool page with one line of code. Free to use, no attribution required (but appreciated).
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