How to Use Cookie Parser in Express: Simple Guide

To use cookie-parser in Express, first install it with npm install cookie-parser. Then import and add it as middleware using app.use(cookieParser()) to access cookies via req.cookies in your routes.

Syntax

The basic syntax to use cookie-parser in Express involves importing the module, then adding it as middleware to your Express app. This middleware parses cookies attached to the client request and makes them available under req.cookies.

• const cookieParser = require('cookie-parser'): Imports the cookie-parser module.
• app.use(cookieParser()): Adds cookie-parser middleware to Express.
• req.cookies: Object containing parsed cookies.

javascript

const express = require('express');
const cookieParser = require('cookie-parser');

const app = express();

app.use(cookieParser());

app.get('/', (req, res) => {
  res.send(req.cookies);
});

Example

This example shows a simple Express server that uses cookie-parser to read cookies sent by the client. When you visit the root URL, it responds with the cookies as a JSON object.

javascript

const express = require('express');
const cookieParser = require('cookie-parser');

const app = express();

// Use cookie-parser middleware
app.use(cookieParser());

// Route to read cookies
app.get('/', (req, res) => {
  res.json({ cookies: req.cookies });
});

// Start server
app.listen(3000, () => {
  console.log('Server running on http://localhost:3000');
});

Output

{"cookies":{}}

Common Pitfalls

Common mistakes when using cookie-parser include:

• Not installing the package before using it.
• Forgetting to add app.use(cookieParser()) before routes that need cookies.
• Trying to access cookies without parsing them first.
• Confusing req.cookies (parsed cookies) with req.headers.cookie (raw cookie string).

Always ensure middleware is added early in the middleware chain.

javascript

/* Wrong way: Missing cookie-parser middleware */
const express = require('express');
const app = express();

app.get('/', (req, res) => {
  // req.cookies is undefined here
  res.send(req.cookies);
});

app.listen(3000);

/* Right way: Add cookie-parser middleware */
const cookieParser = require('cookie-parser');
app.use(cookieParser());

Quick Reference

Step	Code	Description
1	npm install cookie-parser	Install the cookie-parser package
2	const cookieParser = require('cookie-parser')	Import cookie-parser in your app
3	app.use(cookieParser())	Add cookie-parser middleware
4	req.cookies	Access parsed cookies in route handlers

Key Takeaways

Install and import cookie-parser before using it in Express.

Add cookie-parser middleware early with app.use(cookieParser()).

Access cookies easily via req.cookies in your routes.

Do not confuse raw cookie headers with parsed cookies.

Always test that cookies are parsed before using them.