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Võ Huỳnh Đức Minh
Võ Huỳnh Đức Minh

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JSON Web Token: Authorization RESTful API by using JWT

✔ What is JWT

💡 JSON Web Token is an open and standard (RFC 7519) way for you to represent your user’s identity securely during a two-party interaction. Particularly, when two systems exchange data you can use JSON Web Token to identify your user without having to send private credentials on every request.

A JWT typically looks like this


It looks complicated at first sight, but if you understand, the structure of a JWT is just simple as follows

<base64-encoded header>.<base64-encoded payload>.<base64-encoded signature>

In other words, a well-formed JWT consists of three concatenated Base64url-encoded strings, separated by dots (.), which are:

  • Header
  • Payload
  • Signature

✔ Build RESTful API with JWT(JSON Web Token)

First let's create a folder with name "JWT" and take a look at our project structure
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Then open your command line under JWT directory and write this command

npm install --save  express body-parser morgan jsonwebtoken 

1 - index.js

const express = require('express'),
    bodyParser = require('body-parser'), 
    jwt = require('jsonwebtoken'),
    config = require('./configurations/config'),
    cors = require('cors'),
    app = express();

//set secret
app.set('Secret', config.secret);

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: true }));

// parse application/json

app.listen(3000, () => {
    console.log('Server is running on port 3000');
app.get('/', function (req, res) {
    res.send('App is running on http://localhost:3000/');

2 - configurations/config.js

module.exports = {
    secret: "heymynameisminh"

Now check if everthing is okay 😃 Run this command line.

node index.js

❗️ Make sure that you are standing in the right directory to run index.js file (following our project structure)

Open your browser at http://localhost:3000/

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Well done! Everything works well. Keep going

3 - Setting up the authentication system

Assume the username and password in the database are "techx" and "123" then write this code in index.js file'/authenticate', function (req, res) {
    if (req.body.username !== "techx") res.json({ message: "user not found!" });
    if (req.body.password !== "123") res.json({ message: "please check your password!" });
    const payload = {
        check: true
    let token = jwt.sign(payload, app.get('Secret'), {
        expiresIn: 14000
        message: 'authentication done',
        token: token

Now let's make a test with Postman

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Perfect! 😃 We just sent an HTTP request to the server, which responed with the JWT we asked for. For now, Client's already had the token. Let's move to the next step - Setting route

const ProtectedRoutes = express.Router();
app.use('/api', ProtectedRoutes);

ProtectedRoutes.use((req, res, next) => {
    let token = req.headers['access-token'];
    if (!token) res.send({ message: 'No token provided.' });
    jwt.verify(token, app.get('Secret'), (err, decoded) => {
        if (!err) { req.decoded = decoded; next(); }
        return res.json({ message: 'invalid token' });

ProtectedRoutes.get('/getAllProducts', (req, res) => {
    let products = [
            id: 1,
            name: "cheese"
            id: 2,
            name: "carottes"

Everything have done, now we are comparing two different ways of getting data

  • with Token

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  • without Token

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