JWT Parser & Generator
Decode, analyze and generate JWT tokens
JWT Parser
JWT Generator
Header
Payload
Secret
Generated JWT Token
About JWT Parser & Generator Tool
Our JWT (JSON Web Token) Parser & Generator is a comprehensive online tool for working with JWT tokens. JWT is an industry-standard method for securely transmitting information between parties as a JSON object. This tool provides both parsing capabilities to decode existing tokens and generation features to create new ones.
How to Use This JWT Tool
Choose Your Mode
Select "JWT Parser" to decode and analyze existing tokens, or "JWT Generator" to create new tokens with custom header and payload.
Input Your Data
For parsing: paste your JWT token. For generation: edit the header and payload JSON, and provide a secret key for signing.
Process & Copy
Click the action button to parse or generate. Use Ctrl+Enter keyboard shortcut for quick processing. Copy the result with one click.
Key Features
- JWT Parsing: Decode and analyze JWT tokens to view header, payload, and signature
- JWT Generation: Create new JWT tokens with custom header and payload
- HMAC-SHA256 Signing: Secure token signing using industry-standard algorithms
- Timestamp Analysis: Automatic conversion of Unix timestamps to readable dates
- Real-time Validation: Instant validation of JWT structure and JSON format
- Copy to Clipboard: Easy copying of parsed results or generated tokens
- Dual Mode Interface: Switch between parsing and generation modes seamlessly
- Client-Side Processing: All JWT operations happen in your browser for security
Common Use Cases
API Authentication
Debug and test JWT-based authentication flows in REST APIs and microservices. Verify token structure and claims.
SSO Implementation
Analyze and generate tokens for Single Sign-On systems, OAuth 2.0, and OpenID Connect authentication flows.
Token Debugging
Decode JWT tokens to inspect expiration times, user claims, and permissions for troubleshooting authentication issues.
Security Testing
Test token validation, analyze security claims, and verify signature algorithms in penetration testing scenarios.
Understanding JWT Tokens
JSON Web Tokens (JWT) are an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. A JWT consists of three parts separated by dots: Header.Payload.Signature.
Header: Contains the token type (JWT) and the signing algorithm (e.g., HMAC SHA256 or RSA). Payload: Contains claims - statements about an entity (typically the user) and additional data. Common claims include sub (subject), iat (issued at), and exp (expiration). Signature: Ensures the token hasn't been altered. Created by encoding the header and payload, then signing with a secret key.
Best Practices: Always verify signatures, use HTTPS for token transmission, set appropriate expiration times, store secrets securely, and never include sensitive data in the payload (it's base64-encoded, not encrypted).
Frequently Asked Questions
Is JWT encryption or encoding?
JWT uses Base64URL encoding, not encryption. The payload is visible to anyone who has the token. The signature ensures integrity (that the token hasn't been tampered with), but doesn't provide confidentiality. Never put sensitive data like passwords in JWT payloads.
How do I verify a JWT signature?
JWT signatures are verified using the same secret key (for HMAC) or public key (for RSA) that was used to sign it. Our tool shows you the signature component, but actual verification requires the original secret. In production, always verify signatures server-side.
What's the difference between iat, exp, and nbf claims?
iat (issued at) is when the token was created. exp (expiration) is when the token expires and should no longer be accepted. nbf (not before) specifies when the token starts being valid. All are Unix timestamps (seconds since January 1, 1970).
Can I use this tool for production JWT generation?
While our tool uses Web Crypto API for secure signing, JWT generation should always be done server-side in production. Use this tool for testing, learning, and debugging authentication flows.
Is my JWT token sent to your servers?
No, absolutely not. All JWT parsing and generation happens entirely in your browser using JavaScript. Your tokens, secrets, and data never leave your device. You can verify this by checking your browser's network tab.
Privacy & Security
100% Client-Side Processing
All JWT operations are performed locally in your browser using the Web Crypto API. Your tokens, secrets, and sensitive data are never transmitted to our servers or stored anywhere. This tool works completely offline once loaded, ensuring maximum privacy and security for your authentication workflows.