JWT Debugger
Free online JWT debug and inspect token details. Debug JSON Web Tokens with our easy-to-use tool. Supports HS256, RS256, and custom payloads. 100% browser-based.
What Is This?
Debug JSON Web Tokens (JWTs) quickly and securely with our free online JWT tool. JWTs are widely used for API authentication, single sign-on, and secure data exchange. Our tool supports multiple signing algorithms including HS256 and RS256, with real-time payload editing and token inspection. All processing happens locally in your browser for complete security.
How to Use
Enter your JWT token
Paste your JWT token or create a new one by entering the header, payload, and secret key.
Choose signing algorithm
Select the signing algorithm (HS256, HS384, HS512, RS256) and enter your secret or private key.
View decoded data
See the decoded header and payload with formatted JSON output. The tool validates the signature automatically.
Copy the result
Copy the decoded data, modified token, or generated JWT to your clipboard for use in your application.
Examples
Free JWT Debugger tool with no sign-up required
Supports HS256, HS384, HS512, RS256, and ES256 algorithms
Real-time payload editing with formatted JSON preview
Automatic signature validation and error reporting
100% browser-based — tokens never leave your device
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Frequently Asked Questions
What is a JWT?
JSON Web Token (JWT) is a compact, URL-safe token format for securely transmitting claims between parties, commonly used for API authentication and authorization.
What is JWT Debugger?
JWT Debugger is the process of debugging a JSON Web Token to inspect, validate, or create authenticated tokens for secure data exchange.
What algorithms are supported?
We support HS256, HS384, HS512 (HMAC with SHA), RS256 (RSA), and ES256 (ECDSA) signing algorithms.
Is my secret key secure?
Yes, all processing happens in your browser. Your secret key and token data are never sent to any server.