Use Neon with Netlify Functions

Netlify Functions provide a serverless execution environment for building and deploying backend functionality without managing server infrastructure. It's integrated with Netlify's ecosystem, making it ideal for augmenting web applications with server-side logic, API integrations, and data processing tasks in a scalable way.

This guide will show you how to connect to a Neon Postgres database from your Netlify Functions project. We'll use the Neon serverless driver to connect to the database and make queries.

Prerequisites

Before starting, ensure you have:

• 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 Netlify account for deploying your site with Functions. Sign up at Netlify if necessary. While Netlify can deploy directly from a Github repository, we'll use the Netlify CLI tool to deploy our project manually.
• Node.js and npm installed locally for developing and deploying your Functions.

Setting up your Neon database

Initialize a new project

After logging into the Neon Console, proceed to the Projects section.

1. Click New Project to start a new one.

2. In the Neon Dashboard, use the SQL Editor from the sidebar to execute the SQL command below, creating a new table for coffee blends:

   CREATE TABLE favorite_coffee_blends (
       id SERIAL PRIMARY KEY,
       name TEXT,
       notes TEXT
   );

   Populate the table with some initial data:

   INSERT INTO favorite_coffee_blends (name, origin, notes)
   VALUES
       ('Morning Joy', 'Citrus, Honey, Floral'),
       ('Dark Roast Delight', 'Rich, Chocolate, Nutty'),
       ('Arabica Aroma', 'Smooth, Caramel, Fruity'),
       ('Robusta Revolution', 'Strong, Bold, Bitter');

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. It should look similar to this:

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

Keep your connection string handy for later use.

Setting up your Netlify Functions project

We'll use the Netlify CLI to create a new project and add functions to it. To install the CLI, run:

npm install netlify-cli -g

To authenticate the CLI with your Netlify account, run:

netlify login

This command opens a browser window to authenticate your terminal session with Netlify. After logging in, you can close the browser window and interact with your Netlify account from the terminal.

Create a new Netlify project

We will create a simple HTML webpage that fetches the coffee blends from the Neon database using a Netlify Function and displays them. To create a new Netlify Site project, run:

mkdir neon-netlify-example && cd neon-netlify-example
netlify sites:create

You will be prompted to select a team and site name. Choose a unique name for your site. This command then links the current directory to a Site project in your Netlify account.

❯ netlify sites:create
? Team: Ishan Anand’s team
? Site name (leave blank for a random name; you can change it later): neon-netlify-example

Site Created

Admin URL: https://app.netlify.com/sites/neon-netlify-example
URL:       https://neon-netlify-example.netlify.app
Site ID:   ed43ba05-ff6e-40a9-9a68-8f58b9ad9937

Linked to neon-netlify-example

Implement the function

We'll create a new function to fetch the coffee blends from the Neon database. To set up the function entrypoint script, you can run the command below and use the settings provided:

❯ netlify functions:create get_coffee_blends

? Select the type of function you'd like to create Serverless function (Node/Go/Rust)
? Select the language of your function JavaScript
? Pick a template javascript-hello-world
◈ Creating function get_coffee_blends
◈ Created ./netlify/functions/get_coffee_blends/get_coffee_blends.js

Function created!

This command creates a new directory netlify/functions/get_coffee_blends with a get_coffee_blends.js file inside it. We are using the ES6 import syntax to implement the request handler, so we will change the script extension to .mjs for the runtime to recognize it.

We also install the Neon serverless driver as a dependency to connect to the Neon database and fetch the data.

mv netlify/functions/get_coffee_blends/get_coffee_blends.js netlify/functions/get_coffee_blends/get_coffee_blends.mjs
npm install @neondatabase/serverless

Now, replace the contents of the function script with the following code:

// netlify/functions/get_coffee_blends/get_coffee_blends.mjs
import { neon } from '@neondatabase/serverless';

export async function handler(event) {
  const sql = neon(process.env.DATABASE_URL);
  try {
    const rows = await sql('SELECT * FROM favorite_coffee_blends;');
    return {
      statusCode: 200,
      body: JSON.stringify(rows),
    };
  } catch (error) {
    return {
      statusCode: 500,
      body: JSON.stringify({ error: error.message }),
    };
  }
}

This function connects to your Neon database and fetches the list of your favorite coffee blends.

Implement the frontend

To make use of the Function implemented above, we will create a simple HTML page that fetches and displays the coffee information by calling the function.

Create a new file index.html at the root of your project with the following content:

<!doctype html>
<html>
  <head>
    <title>Coffee Blends</title>
  </head>
  <body>
    <h1>My favourite coffee blends</h1>
    <ul id="blends"></ul>
    <script>
      (async () => {
        try {
          const response = await fetch('/.netlify/functions/get_coffee_blends');
          const blends = await response.json();
          const blendsList = document.getElementById('blends');
          blends.forEach((blend) => {
            const li = document.createElement('li');
            li.innerText = `${blend.name} - ${blend.notes}`;
            blendsList.appendChild(li);
          });
        } catch (error) {
          console.error('Error:', error);
        }
      })();
    </script>
  </body>
</html>

Test the site locally

Set the DATABASE_URL environment variable in a .env file at the root of your project:

DATABASE_URL=YOUR_NEON_CONNECTION_STRING

We are now ready to test our Netlify site project locally. Run the following command to start a local development server:

netlify dev

The Netlify CLI will print the local server URL where your site is running. Open the URL in your browser to see the coffee blends fetched from your Neon database.

Deploying your Netlify Site and Function

Deploying is straightforward with the Netlify CLI. However, we need to set the DATABASE_URL environment variable for the Netlify deployed site too. You can use the CLI to set it.

netlify env:set DATABASE_URL "YOUR_NEON_CONNECTION_STRING"

Now, to deploy your site and function, run the following command. When asked to provide a publish directory, enter . to deploy the entire project.

netlify deploy --prod

The CLI will build and deploy your site and functions to Netlify. After deployment, Netlify provides a URL for your live function. Navigate to the URL in your browser to check that the deployment was successful.

Removing the example application and Neon project

For cleanup, delete your Netlify site and functions via the Netlify dashboard or CLI. Consult the Netlify documentation for detailed instructions.

To remove your Neon project, follow the deletion steps in Neon's documentation under Manage Projects.

Source code

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

• Use Neon with Netlify Functions

  Connect a Neon Postgres database to your Netlify Functions application

Resources

• Netlify Functions
• Netlify CLI
• Neon