JWT Decoder & Debugger: Inspect Your Auth Tokens
Debug your authentication flow effortlessly. Our free tool breaks down any JWT into its Header, Payload, and Signature, allowing you to verify claims and troubleshoot integration issues in seconds.
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JWT Decoder & Encoder Instantly Decode or Create JSON Web Tokens
Our free JWT Decoder & Encoder helps you securely inspect, decode, and generate JSON Web Tokens in a user-friendly way. Whether you're a backend developer, security tester, or someone learning about token-based authentication, this tool makes handling JWTs quick and effortless.
Simply paste your JWT to instantly decode its header, payload, and signature. Since JWTs are essentially structured strings, you might also find our Base64 Encoder & Decoder useful for manually inspecting the individual parts of a token. For those working with signature verification and data integrity, our SHA-256 Hash Generator is an essential tool to have in your security toolkit.
JSON Web Tokens (JWTs) are widely used for API authentication, stateless session handling, and secure data transfer. This tool is ideal for debugging JWTs, verifying signatures, or testing with different claims. No login or server processing is required everything runs securely in your browser.
Key Features of Our JWT Decoder & Encoder
- Decode JWT tokens instantly to view the header, payload, and signature
- Generate signed JWTs using your own payload and secret
- Supports HS256 and RS256 algorithms
- Client-side processing for maximum security
- Live preview and auto-update as you type
- Free to use with no ads or login required
What is a JWT?
A JWT (JSON Web Token) is a compact, URL-safe token format used to represent claims between two parties. It consists of three parts: a header, a payload (containing the claims), and a signature. JWTs are the industry standard for authorization and information exchange in modern web applications.
Is This JWT Tool Safe?
Yes, absolutely. This JWT Decoder & Encoder tool runs entirely in your browser. Nothing is sent to any server, ensuring that your sensitive tokens and secrets remain private. It's perfect for debugging JWTs you receive from APIs or generating your own tokens during development without risking data leaks.
Frequently Asked Questions (FAQs)
1. Is this JWT tool free to use?
Yes, JWT Decoder & Encoder tool is completely free and doesn't require any sign-up, subscription, or payment.
2. Are my tokens or secrets stored on your server?
No. All operations are performed client-side using JavaScript. Your tokens and secrets never leave your device.
3. Can I validate a JWT's signature here?
Yes. By entering the token and the corresponding secret key or public key, the tool will verify if the signature is valid.
4. Which algorithms does this tool support?
The tool currently supports the most common algorithms, including HS256 (HMAC with SHA-256) and RS256 (RSA Signature with SHA-256).
5. Can I edit the payload and generate a new token?
Yes. You can modify the JSON payload in the editor, and the encoder will generate a new signed JWT in real-time.
6. What happens if my JWT is invalid?
The JWT Decoder & Encoder tool will display an error message if the token is malformed or if the signature verification fails due to an incorrect secret.
7. Why are JWTs Base64 encoded?
Base64 encoding makes the token URL-safe, allowing it to be easily passed in HTTP headers or query parameters without breaking.
8. Can I use this for production tokens?
While the tool is secure (local processing), we recommend using it primarily for debugging and development testing purposes.
9. Does the tool support nested JSON in the payload?
Yes, as long as the payload is a valid JSON object, you can include nested objects and arrays as claims.
10. Do I need an internet connection to use this?
You need to load the page initially, but since the logic is client-side, the decoding and encoding process works within your browser environment.