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Stream database changes in real-time with Prisma Pulse

Learn how to create event-driven flows on your backend triggered by changes in your Neon Postgres database

Neon's Logical Replication feature enables you to subscribe to changes in your database, supporting things like replication or creating event-driven functionality.

Prisma Pulse is a fully managed, production-ready service that connects to your Neon Postgres database, and allows you to stream changes from your database in real-time, integrated closely with Prisma ORM.

In this guide, you will learn how to set up Prisma Pulse with your Neon database and create your first event stream.

tip

What can you make with database event-driven architecture?

Set up real-time triggers for your Inngest workflows, re-index your TypeSense search whenever data changes, and much more.

Prerequisites

Enable logical replication in Neon

important

Enabling logical replication modifies the Postgres wal_level configuration parameter, changing it from replica to logical for all databases in your Neon project. Once the wal_level setting is changed to logical, it cannot be reverted. Enabling logical replication also restarts all computes in your Neon project, meaning active connections will be dropped and have to reconnect.

To enable logical replication in Neon:

  1. Select your project in the Neon Console.
  2. On the Neon Dashboard, select Project settings.
  3. Select Beta.
  4. Click Enable to enable logical replication.

You can verify that logical replication is enabled by running the following query from the Neon SQL Editor:

SHOW wal_level;
 wal_level
-----------
 logical

Connect Prisma Pulse

  1. If you haven't already done so, create a new account or sign in on the Prisma Data Platform.
  2. In the Prisma Data Platform Console create a new project by clicking the New project button.
  3. In the New project configuration, select Pulse as your starting point.
  4. Copy your database connection string from Neon into the database connection input field on the Platform Console.
  5. Choose a region that is closest to your Neon database.
  6. Click Create project.
  7. We recommend leaving Event persistence switched on (default). This means Prisma Pulse will automatically store events in the case your server goes down, allowing you to resume again with zero data loss.
  8. Click Enable Pulse.
  9. After Pulse has been enabled (this may take a moment), generate an API key by clicking Generate API key. Save this for later.

Your first stream

Set up your project

Create a new TypeScript project with Prisma:

npx try-prisma -t typescript/starter

If you already have a TypeScript project with Prisma client installed, you can skip this.

From the root of your project, install the Pulse extension

npm install @prisma/extension-pulse@latest

Extend your Prisma Client instance with the Pulse extension

Add the following to extend your existing Prisma Client instance with the Prisma Pulse extension. Don't forget to insert your own API key.

import { PrismaClient } from '@prisma/client';
import { withPulse } from '@prisma/extension-pulse';

const prisma = new PrismaClient().$extends(withPulse({ apiKey: '<your Pulse API key>' }));

note

For a real production use case, you should consider moving sensitive values like your API key into environment variables.

Create your first Pulse stream

The code below subscribes to a User model in your Prisma schema. You can use a similar approach to subscribe to any model that exists in your project.

import { PrismaClient } from '@prisma/client';
import { withPulse } from '@prisma/extension-pulse';

const prisma = new PrismaClient().$extends(withPulse({ apiKey: '<your Pulse API key>' }));

async function main() {
  // Create a stream from the 'User' model
  const stream = await prisma.user.stream({ name: 'user-stream' });

  for await (const event of stream) {
    console.log('Just received an event:', event);
  }
}

main();

Trigger a database change

You can use Prisma Studio to easily make changes in your database, to trigger events. Open Prisma Studio by running: npx prisma studio

After making a change in Studio, you should see messages appearing in your terminal like this:

Just received an event: {
  action: 'create',
  created: {
    id: 'clzvgzq4b0d016s28yluse9r1',
    name: 'Polly Pulse',
    age: 35
  },
  id: '01J5BCFR8F8DBJDXAQ5YJPZ6VY',
  modelName: 'User'
}

What's next?

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