JWT Decoder
Decode and inspect JWT tokens. Includes header inspection and payload decoding. Runs locally in your browser — free, no signup, no install, no data upload.
Developer ToolsAbout this tool
Inspect JSON Web Tokens (JWTs) safely in the browser: decode the header and payload to see claims, algorithms, and expiry without sending the token to a server.
Useful for debugging OAuth flows, API integrations, and mobile or SPA auth—especially when you need to verify what a token actually contains.
Features
- Header and payload decoding (Base64URL)
- Human-readable claim display
- Signature section awareness (verification depends on your keys)
- Client-side processing for typical inspection workflows
How to decode a JWT
- Paste the tokenPaste the full JWT string (three dot-separated segments) into the tool.
- Review header and payloadRead the algorithm, issuer, audience, expiry, and custom claims shown in the decoded panels.
- Validate separately if neededCryptographic signature verification requires your secret or public key—use your auth library or server for production checks.
Guides
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Developer ToolsFrequently Asked Questions
Is it safe to paste JWTs here?
Treat tokens like passwords. This tool decodes locally in the browser for typical debugging, but do not paste production secrets in shared or recorded sessions. Revoke tokens if they are exposed.
Does this verify the signature?
Decoding shows what is inside the token. Full signature verification needs your key material and is usually done on the server or with your auth SDK.
What does the JWT Decoder tool do?
Decode and inspect JWT tokens. Includes header inspection and payload decoding. Runs locally in your browser — free, no signup, no install, no data upload. It is listed under Developer Tools on FreeEasyToolsOnline.
Is my data sent to your servers?
Most processing for this tool runs in your browser. Do not paste secrets you cannot afford to expose, and read any on-page warnings for tools that intentionally call external APIs.
Do I need to install anything?
No. Use a modern desktop or mobile browser. For best results, keep the page open until processing finishes for large files or long operations.