Connect an Express application to Neon

Pre-built prompt for connecting ExpressJS applications to Lakebase Postgres

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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.

1. 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.

2. Create an Express project and add dependencies

   1. Create an Express project and change to the newly created directory.

      mkdir neon-express-example
      cd neon-express-example
      npm init -y
      npm install express

   2. Add project dependencies using one of the following commands:

      Neon serverless drivernode-postgrespostgres.js

      npm install @neondatabase/serverless dotenv

3. 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 on your Project Dashboard to open the Connect to your database modal. Select Node.js from the Connection string dropdown. For more information, see Connect from any application.

   DATABASE_URL="postgresql://<user>:<password>@<endpoint_hostname>.neon.tech:<port>/<dbname>?sslmode=require&channel_binding=require"

   important

   Never hardcode credentials in source code files. Always use environment variables via process.env. For more information, see Security overview.

4. 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 drivernode-postgrespostgres.js

   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}`);
   });

5. Run index.js

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

   { 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.

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