- 1Choose file
- 2Adjust
- 3Download
JWT Debugger & Inspector online, free
Decode JSON Web Tokens into Header, Payload, and Claims, format timestamps, and check validity without sending sensitive tokens to any server.
- Runs in your browser — no upload
- Free, no sign-up, no watermark
- TXT
How to use JWT Debugger & Inspector · JWT Debugger & Inspector — frequently asked questions
How to use JWT Debugger & Inspector
- 1
Add your TXT file
Drop a file on the page, paste it, or click Select Files. Nothing is uploaded — it opens straight in your browser.
- 2
Fine-tune the settings
The defaults already suit most files; change them only if you need to.
- 3
Run JWT Debugger & Inspector
Press the start button. Processing happens on your device, usually in seconds.
- 4
Download the result
Save the finished file, or continue with another tool without downloading in between.
What JWT Debugger & Inspector can do
- Private by design — files are processed in your browser and never uploaded
- Free with no sign-up, no watermark and no daily limit
JWT Debugger & Inspector — frequently asked questions
Is it safe to paste production JWT tokens into this debugger?
Yes. Unlike third-party token debuggers that transmit payloads over HTTP to remote servers, our tool runs 100% client-side in your local web browser. Your JWT tokens, claims, and credentials never touch a network connection.
What components does the JWT Debugger decode?
It splits the standard dot-separated token into its three constituent parts: the Header (algorithm & token type), the Payload (registered and custom claims), and the Signature.
Does it check token expiration?
Yes. The debugger automatically reads standard registered claims like `exp` (expiration time), `iat` (issued at), and `nbf` (not before), displaying human-readable timestamps and highlighting expired status.
Can I verify cryptographic signatures?
The tool inspects the declared algorithm (`alg`, such as HS256, RS256, or ES256) and parses the signature block, verifying token structure and formatting without needing private keys.
Can I edit claims or test malformed tokens?
Yes. The debugger provides descriptive syntax and base64url decoding error notices when an entered token contains illegal padding or invalid JSON.
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