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JWT Tokens

JSON Web Tokens (JWT) provide a secure method for transmitting information between parties as a JSON object.

JWT Structure

A JWT consists of three parts separated by dots:

header.payload.signature

Header 

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload 

{
  "sub": "1234567890",
  "email": "[email protected]",
  "iat": 1516239022,
  "exp": 1516242622
}

Signature

The signature is created using:

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  secret
)

Creating JWT Tokens

Node.js Example 

const jwt = require('jsonwebtoken');


const payload = {
  userId: '12345',
  email: '[email protected]',
  scope: ['email', 'contacts']
};


const token = jwt.sign(payload, process.env.JWT_SECRET, {
  expiresIn: '1h',
  issuer: 'your-app',
  audience: 'brevo-api'
});

Python Example 

import jwt
import datetime


payload = {
    'user_id': '12345',
    'email': '[email protected]',
    'exp': datetime.datetime.utcnow() + datetime.timedelta(hours=1),
    'iat': datetime.datetime.utcnow()
}


token = jwt.encode(payload, 'your-secret-key', algorithm='HS256')

Using JWT with Brevo API

Terminal window
curl -X GET "https://api.brevo.com/v3/account" \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..." \
  -H "Accept: application/json"

Token Validation 

const validateToken = (token) => {
  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    return { valid: true, payload: decoded };
  } catch (error) {
    return { valid: false, error: error.message };
  }
};

Best Practices

  • Use strong, random secrets
  • Set appropriate expiration times
  • Validate tokens on every request
  • Use HTTPS only
  • Store secrets securely
  • Implement token refresh logic