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JWT Encoder/Decoder
Encode and decode JSON Web Tokens (JWT) with header, payload, and signature validation
jwtjsonwebtokenencodedecodesecurity
Mode Selection
JWT Token
Header
Payload
Signature
About JWT
🔐 What is JWT?
JSON Web Token is a compact, URL-safe means of representing claims to be transferred between two parties.
🏗️ JWT Structure
A JWT consists of three parts: Header, Payload, and Signature, separated by dots (.).
⚠️ Security Note
This tool is for educational purposes. Never use weak secrets in production environments.
📅 Expiration
The tool automatically checks if a JWT token is expired based on the "exp" claim.
About JWT Encoder/Decoder
The JWT Encoder/Decoder tool provides a complete solution for working with JSON Web Tokens. Whether you need to decode existing tokens to inspect their contents or create new tokens for authentication, this tool supports the full JWT specification with proper Base64URL encoding and HMAC-SHA256 signatures.
✨ Key Benefits
- Complete JWT encoding and decoding capabilities
- Real-time token validation and expiration checking
- Secure HMAC-SHA256 signature generation
- Educational tool for understanding JWT structure
- Support for custom headers and payloads
🚀 Features
- Decode JWT tokens into readable components
- Encode custom JWT tokens with headers and payloads
- HMAC-SHA256 signature generation using Web Crypto API
- Token expiration validation
- Copy individual components or complete tokens
- Sample data loading for testing
- Real-time JSON validation
💡 Use Cases
- API authentication and authorization
- Stateless session management
- Single sign-on (SSO) implementations
- Microservices communication
- Mobile app authentication
- OAuth 2.0 and OpenID Connect
- Debugging JWT-based applications
🎯 Fun Facts
- JWT tokens are self-contained and stateless
- JWT is pronounced 'jot' by many developers
- A JWT token has exactly 3 parts separated by dots
- JWT can carry custom claims beyond the standard ones
📚 Historical Context
- JWT was first defined in RFC 7519 in 2015
- JWT evolved from Simple Web Token (SWT) and SAML tokens
- JSON Web Signature (JWS) and JSON Web Encryption (JWE) are related standards
- JWT became popular with REST APIs and microservices