Use Neon with Cloudflare Workers

Cloudflare Workers is a serverless platform allowing you to deploy your applications globally across Cloudflare's network. It supports running JavaScript, TypeScript, and WebAssembly, making it a great choice for high-performance, low-latency web applications.

This guide demonstrates how to connect to a Neon Postgres database from your Cloudflare Workers application. We'll use the Neon serverless driver to connect to the database and make queries.

Prerequisites

To follow along with this guide, you will need:

• A Neon account. If you do not have one, sign up at Neon. Your Neon project comes with a ready-to-use Postgres database named neondb. We'll use this database in the following examples.
• A Cloudflare account. If you do not have one, sign up for Cloudflare Workers to get started.
• Node.js and npm installed on your local machine. We'll use Node.js to build and deploy the Workers application.

Setting up your Neon database

Initialize a new project

Log in to the Neon Console and navigate to the Projects section.

1. Click the New Project button to create a new project.

2. From the Neon Dashboard, navigate to the SQL Editor from the sidebar, and run the following SQL command to create a new table in your database:

   CREATE TABLE books_to_read (
       id SERIAL PRIMARY KEY,
       title TEXT,
       author TEXT
   );

   Next, insert some sample data into the books_to_read table so that you can query it later:

   INSERT INTO books_to_read (title, author)
   VALUES
       ('The Way of Kings', 'Brandon Sanderson'),
       ('The Name of the Wind', 'Patrick Rothfuss'),
       ('Coders at Work', 'Peter Seibel'),
       ('1984', 'George Orwell');

Retrieve your Neon database connection string

Log in to the Neon Console and navigate to the Connection Details section to find your database connection string. Select the Pooled connection option to add the -pooler option to your connection string. A pooled connection is recommended for serverless environments. For more information, see Connection pooling.

Your pooled connection string should look similar to this:

postgresql://alex:AbC123dEf@ep-cool-darkness-123456-pooler.us-east-2.aws.neon.tech/dbname?sslmode=require

Keep your connection string handy for later use.

Setting up your Cloudflare Workers project

Create a new Worker project

Run the following command in a terminal window to set up a new Cloudflare Workers project:

npm create cloudflare@latest

This initiates an interactive CLI prompt to generate a new project. To follow along with this guide, you can use the following settings:

├ In which directory do you want to create your application?
│ dir ./my-neon-worker
│
├ What type of application do you want to create?
│ type "Hello World" Worker
│
├ Do you want to use TypeScript?
│ no typescript

When asked if you want to deploy your application, select no. We'll develop and test the application locally before deploying it to Cloudflare Workers platform.

The create-cloudflare CLI installs the Wrangler tool to manage the full workflow of testing and managing your Worker applications.

Implement the Worker script

We'll use the Neon serverless driver to connect to the Neon database, so you need to install it as a dependency:

npm install @neondatabase/serverless

Now, you can update the src/index.js file in the project directory with the following code:

import { Client } from '@neondatabase/serverless';

export default {
  async fetch(request, env, ctx) {
    const client = new Client(env.DATABASE_URL);
    await client.connect();
    const { rows } = await client.query('SELECT * FROM books_to_read;');
    return new Response(JSON.stringify(rows));
  },
};

The fetch handler defined above gets called when the worker receives an HTTP request. It will query the Neon database to fetch the full list of books in our to-read list.

Test the worker application locally

You first need to configure the DATABASE_URL environment variable to point to our Neon database. You can do this by creating a .dev.vars file at the root of the project directory with the following content:

DATABASE_URL=YOUR_NEON_CONNECTION_STRING

Now, to test the worker application locally, you can use the wrangler CLI which comes with the Cloudflare project setup.

npx wrangler dev

This command starts a local server and simulates the Cloudflare Workers environment.

❯ npx wrangler dev
 ⛅️ wrangler 3.28.1
-------------------
Using vars defined in .dev.vars
Your worker has access to the following bindings:
- Vars:
  - DATABASE_URL: "(hidden)"
⎔ Starting local server...
[wrangler:inf] Ready on http://localhost:8787

You can visit http://localhost:8787 in your browser to test the worker application. It should return a JSON response with the list of books from the books_to_read table.

[{"id":1,"title":"The Way of Kings","author":"Brandon Sanderson"},{"id":2,"title":"The Name of the Wind","author":"Patrick Rothfuss"},{"id":3,"title":"Coders at Work","author":"Peter Seibel"},{"id":4,"title":"1984","author":"George Orwell"}]

Deploying your application with Cloudflare Workers

Authenticate Wrangler with your Cloudflare account

Run the following command to link the Wrangler tool to your Cloudflare account:

npx wrangler login

This command will open a browser window and prompt you to log into your Cloudflare account. After logging in and approving the access request for Wrangler, you can close the browser window and return to your terminal.

Add your Neon connection string as a secret

Use Wrangler to add your Neon database connection string as a secret to your Worker:

npx wrangler secret put DATABASE_URL

When prompted, paste your Neon connection string.

Publish your Worker application and verify the deployment

Now, you can deploy your application to Cloudflare Workers by running the following command:

npx wrangler deploy

The Wrangler CLI will output the URL of your Worker hosted on the Cloudflare platform. Visit this URL in your browser or use curl to verify the deployment works as expected.

❯ npx wrangler deploy
 ⛅️ wrangler 3.28.1
-------------------
Total Upload: 189.98 KiB / gzip: 49.94 KiB
Uploaded my-neon-worker (4.03 sec)
Published my-neon-worker (5.99 sec)
  https://my-neon-worker.anandishan2.workers.dev
Current Deployment ID: de8841dd-46e4-436d-b2c4-569e91f54c72

Removing the example application and Neon project

To delete your Worker, you can use the Cloudflare dashboard or run wrangler delete from your project directory, specifying your project name. Refer to the Wrangler documentation for more details.

To delete your Neon project, follow the steps outlined in the Neon documentation under Delete a project.

Source code

You can find the source code for the application described in this guide on GitHub.

• Use Neon with Cloudflare Workers

  Connect a Neon Postgres database to your Cloudflare Workers application

Resources

• Cloudflare Workers
• Wrangler CLI
• Neon