Express + a Database

No database built in

Express has no opinion on storage. For MongoDB, apps commonly use Mongoose (an ODM); for PostgreSQL/MySQL, the pg driver or an ORM like Prisma.

A minimal Mongoose route

Connect once at startup, then use a model inside route handlers.

import mongoose from 'mongoose';

await mongoose.connect(process.env.MONGO_URI);

const User = mongoose.model('User', new mongoose.Schema({
  name: String,
  email: String,
}));

app.get('/users', async (req, res, next) => {
  try {
    const users = await User.find();
    res.json(users);
  } catch (err) {
    next(err);
  }
});

Quick check: What is Mongoose?

• A CSS framework
• A replacement for Express itself
• A template engine
• An ODM for modeling MongoDB data in Node