JWT Debugger
Decode JSON Web Tokens to inspect the header and payload. View claims and expiry in readable JSON.
About This Free Online JWT Debugger
Our free online JWT debugger decodes JSON Web Tokens so you can inspect what is inside them. Paste a token and the tool splits it into its three parts, base64url-decodes the header and payload, and pretty-prints them as readable JSON. It also highlights standard claims like issued-at and expiry, showing whether the token has expired. Decoding happens entirely in your browser — your tokens are never sent anywhere. Perfect for debugging authentication during development.
Features of Our JWT Debugger
- Decode JWT header and payload to readable JSON
- Highlights standard claims (iat, exp, iss, sub)
- Shows token expiry status
- Handles base64url encoding correctly
- Live decoding as you paste
- 100% private — tokens never leave your browser
How to Use the JWT Debugger
Using this tool is simple and requires no signup or registration. Follow these steps:
- Paste your JSON Web Token into the input field.
- See the decoded header and payload as formatted JSON.
- Check the highlighted claims and expiry status.
- Copy any decoded section you need.
Frequently Asked Questions About JWT Debugger
Does this verify the JWT signature?
No. This tool decodes the token to show its contents, which does not require the secret key. Verifying the signature requires the server's secret or public key and should be done server-side. Decoding never proves a token is authentic.
Is it safe to paste my token here?
Yes. All decoding happens locally in your browser using JavaScript. Your token is never uploaded, logged, or stored. That said, avoid sharing production tokens publicly anywhere.
What are the three parts of a JWT?
A JWT has a header, a payload, and a signature, separated by dots. The header describes the algorithm, the payload holds the claims (data), and the signature verifies integrity. This tool decodes the header and payload.
Why Choose Text Toolbox?
Text Toolbox provides free, private, and instant online text tools. Unlike other text utility websites that require signup accounts or send your data to servers, all our tools process your text entirely in your browser. This means your content never leaves your device — we cannot see it, store it, or share it. Our tools are fast, lightweight, and work on any device with a modern web browser.