Connect an Express application to Neon

This guide describes how to create a Neon project and connect to it from an Express application to query a Lakebase Postgres database. Choose a driver. @neondatabase/serverless connects over HTTP or W...

Pre-built prompt for connecting ExpressJS applications to Lakebase Postgres

This guide describes how to create a Neon project and connect to it from an Express application to query a Lakebase Postgres database.

Choose a driver

@neondatabase/serverless connects over HTTP or WebSockets instead of TCP. Use it for serverless and edge platforms without built-in connection pooling (Vercel, Netlify Functions, Deno Deploy, Cloudflare Workers without Hyperdrive).
postgres (postgres.js) is a fast, full-featured client for both serverless and traditional Node.js server environments.
pg (node-postgres) is the classic, widely-used driver for traditional, long-running Node.js servers. Also the standard choice for Vercel Fluid compute and Cloudflare with Hyperdrive.

For a detailed comparison including all platforms, see Choosing your connection method.

Create a Neon project
If you do not have one already, create a Neon project.
1. Navigate to the Projects page in the Neon Console.
2. Click New Project.
3. Specify your project settings and click Create Project.
Create an Express project and add dependencies
1. Create an Express project and change to the newly created directory.
  Bash
```
mkdir neon-express-example
cd neon-express-example
npm init -y
npm install express
```
2. Add project dependencies using one of the following commands:npm install @neondatabase/serverless dotenvnpm install pg dotenvnpm install postgres dotenv
Store your Neon credentials
Add a .env file to your project directory and add your Neon connection details to it. Find your database connection details by clicking the Connect button in the Console nav to open the Connect to your branch modal. Select Node.js from the Connection string dropdown. For more information, see Connect from any application.
Bash
```
DATABASE_URL="postgresql://<user>:<password>@<endpoint_hostname>.neon.tech:<port>/<dbname>?sslmode=require&channel_binding=require"
```
Never hardcode credentials in source code files. Always use environment variables via process.env. For more information, see Security overview.

Configure the Postgres client

Add an index.js file to your project directory and add the following code snippet to connect to your Neon database:

Neon serverless driver

require('dotenv').config();

const express = require('express');
const { neon } = require('@neondatabase/serverless');

const app = express();
const PORT = process.env.PORT || 4242;

const sql = neon(process.env.DATABASE_URL);

app.get('/', async (req, res) => {
  try {
    const [result] = await sql`SELECT version()`;
    const version = result?.version || 'No version found';
    res.json({ version });
  } catch (error) {
    console.error('Database query failed:', error);
    res.status(500).json({ error: 'Failed to connect to the database.' });
  }
});

app.listen(PORT, () => {
  console.log(`Listening to http://localhost:${PORT}`);
});

node-postgres

require('dotenv').config();

const express = require('express');
const { Pool } = require('pg');

const app = express();
const PORT = process.env.PORT || 4242;

const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
});

app.get('/', async (req, res) => {
  let client;
  try {
    client = await pool.connect();
    const { rows } = await client.query('SELECT version()');
    const version = rows[0]?.version || 'No version found';
    res.json({ version });
  } catch (error) {
    console.error('Database query failed:', error);
    res.status(500).json({ error: 'Failed to connect to the database.' });
  } finally {
    client?.release();
  }
});

app.listen(PORT, () => {
  console.log(`Listening to http://localhost:${PORT}`);
});

postgres.js

require('dotenv').config();

const express = require('express');
const postgres = require('postgres');

const app = express();
const PORT = process.env.PORT || 4242;

const sql = postgres(process.env.DATABASE_URL);

app.get('/', async (req, res) => {
  try {
    const [result] = await sql`SELECT version()`;
    const version = result?.version || 'No version found';
    res.json({ version });
  } catch (error) {
    console.error('Database query failed:', error);
    res.status(500).json({ error: 'Failed to connect to the database.' });
  }
});

app.listen(PORT, () => {
  console.log(`Listening to http://localhost:${PORT}`);
});

Run index.js

Run node index.js to view the result on localhost:4242 as follows:

Bash

{ version: 'PostgreSQL 16.0 on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit' }

Connection issues

If you see an endpoint ID is not specified error, the TLS client your Postgres driver depends on doesn't support Server Name Indication (SNI), which Neon uses to route connections. For pg (node-postgres), this means an outdated libpq-compatible TLS stack; upgrading pg usually resolves it.
If you encounter an SSL SYSCALL error: EOF detected (or a similar connection-reset error), this typically happens when an application tries to reuse a connection after the Neon compute has been suspended due to inactivity. This mainly affects long-running servers that keep a connection pool open, like the pg example above — closing and recreating idle connections, or reconnecting on error, resolves it.

Notes for AI-assisted setup

Do not hardcode credentials or connection strings in any .js source file. Always use environment variables via process.env and dotenv.
Wrap all database queries in a try...catch block. Return a 500 status with an error message on failure.
When using pg (node-postgres), declare let client before the try block and call client?.release() in the finally block. This safely handles cases where pool.connect() itself fails.
Initialize the connection pool or client outside the route handler, not inside it. Creating a new pool on every request wastes resources.
Choose the right driver for your platform. @neondatabase/serverless is for serverless/edge platforms without TCP support. For long-running Express servers, use pg or postgres. See Choosing your connection method.

Next steps

Set up Managed Better Auth: Add managed authentication that branches with your database
Add Object Storage: S3-compatible file storage that branches with your database
Deploy a Function: Run backend compute next to your database, no separate hosting needed
Call an LLM with AI Gateway: Access foundation models from Anthropic, OpenAI, Google, and more with one credential

Need help?

Join our Discord Server to ask questions or see what others are doing with Neon. For paid plan support options, see Support.

Search documentation

Neon Docs

Connect an Express application to Neon

Choose a driver

Connection issues

Next steps

Need help?

Neon Docs