JWT Tester
Decode, verify, and generate JSON Web Tokens with multiple algorithms and validation
Quick Examples
JWT Token
Implementation Examples
// Install: npm install jsonwebtoken
const jwt = require('jsonwebtoken');
// Generate JWT
const token = jwt.sign(
{
"sub": "1234567890",
"name": "John Doe",
"iat": 1760621794
},
'your-256-bit-secret',
{ algorithm: 'HS256' }
);
// Verify JWT
try {
const decoded = jwt.verify(token, 'your-256-bit-secret');
console.log('Valid token:', decoded);
} catch (error) {
console.error('Invalid token:', error.message);
}JWT Best Practices
• Always use HTTPS to prevent token interception
• Store tokens securely (httpOnly cookies or secure storage)
• Keep tokens short-lived and implement refresh tokens
• Never store sensitive data in the payload (it's not encrypted)
• Validate token signature on every request
• Use strong secret keys (minimum 256 bits for HS256)
• Implement token blacklisting for logout functionality