In this quickstart, you’ll create a real-time data pipeline that streams changes from a Postgres database to a Sequin Stream. Sequin Stream is a Postgres-based message stream, native to Sequin.

You’ll:

  • Boot Sequin
  • Connect to a sample playground database
  • Create a Sequin Stream to receive database changes
  • See your changes flow in real-time

By the end, you’ll have hands-on experience setting up Postgres change data capture (CDC) with Sequin and Sequin Stream.

This is the quickstart for streaming Postgres to Sequin Stream. See the how-to guide for an explanation of how to use the Sequin Stream sink or the reference for details on all configuration options.

Run Sequin

The easiest way to get started with Sequin is with our Docker Compose file. This file starts a Postgres database, Redis instance, and Sequin server.

1

Create directory and start services

  1. Download sequin-docker-compose.zip.
  2. Unzip the file.
  3. Navigate to the unzipped directory and start the services:
cd sequin-docker-compose && docker compose up -d
2

Verify services are running

Check that Sequin is running using docker ps:

docker ps

You should see output like the following:

CONTAINER ID   IMAGE                           COMMAND                  CREATED          STATUS                    PORTS                              NAMES
bd5c458cabde   sequin/sequin:latest            "/scripts/start_comm…"   11 seconds ago   Up 9 seconds              4000/tcp, 0.0.0.0:7376->7376/tcp   sequin-sequin-1
3bacd89765e7   grafana/grafana                 "/run.sh"                11 seconds ago   Up 11 seconds             0.0.0.0:3000->3000/tcp             sequin-sequin_grafana-1
3ad41319a66c   postgres:16                     "docker-entrypoint.s…"   11 seconds ago   Up 11 seconds (healthy)   0.0.0.0:7377->5432/tcp             sequin-sequin_postgres-1
6139a5fc4e80   redis:7                         "docker-entrypoint.s…"   11 seconds ago   Up 11 seconds             0.0.0.0:7378->6379/tcp             sequin-sequin_redis-1
7e07a5b052de   prom/prometheus                 "/bin/prometheus --c…"   11 seconds ago   Up 11 seconds             0.0.0.0:9090->9090/tcp             sequin-sequin_prometheus-1

Sequin, Postgres, Redis, Prometheus, and Grafana should be up and running (status: Up).

Login

The Docker Compose file automatically configures Sequin with an admin user and a playground database.

Let’s log in to the Sequin web console:

1

Open the web console

After starting the Docker Compose services, open the Sequin web console at http://localhost:7376:

2

Login with default credentials

Use the following default credentials to login:

  • Email:
admin@sequinstream.com
  • Password:
sequinpassword!

View the playground database

To get you started quickly, Sequin’s Docker Compose file creates a logical database called sequin_playground with a sample dataset in the public.products table.

Let’s take a look:

1

Navigate to Databases

In the Sequin web console, click Databases in the sidebar.

2

Select playground database

Click on the pre-configured sequin-playground database:

The database “Health” should be green.

3

View contents of the products table

Let’s get a sense of what’s in the products table. Run the following command:

docker exec -i sequin-sequin_postgres-1 \
  psql -U postgres -d sequin_playground -c \
  "select id, name, price from products;"

This command connects to the running Postgres container and runs a psql command.

You should see a list of the rows in the products table:

  id |         name          | price 
----+-----------------------+-------
  1 | Avocados (3 pack)     |  5.99
  2 | Flank Steak (1 lb)    |  8.99
  3 | Salmon Fillet (12 oz) | 14.99
  4 | Baby Spinach (16 oz)  |  4.99
  5 | Sourdough Bread       |  6.99
  6 | Blueberries (6 oz)    |  3.99
(6 rows)

We’ll make modifications to this table in a bit.

Create a Sequin Stream Sink

With the playground database connected, you can create a sink. This sink will send changes to the products table to a Sequin Stream:

1

Navigate to Sinks

Click “Sinks” in the sidebar navigation, then click “Create Sink”.

2

Select sink type

Select “Sequin Stream” as the sink type and click “Continue”.

3

Note "Source" configuration

In the “Source” card, note that the sequin-playground database is selected and all schemas and tables are included. Leave these defaults:

4

Setup a backfill

In the Inital backfill card, select the public.products table to initate a backfill when the sink is created.

5

Create the sink

You can leave the rest of the defaults. As configured, the Sequin Stream will first receive a backfill of all rows currently in the products table. Then, it will receive all changes to the products table in real-time.

Click “Create Sink” to finish setting up your Sequin Stream.

See changes flow to your Sequin Stream

On the new sink’s overview page, you should see the “Health” status turn green, indicating data is flowing to your stream.

Let’s confirm messages are flowing:

1

Messages tab

Click the “Messages” tab. You’ll see a bunch of messages are available, pending delivery:

Sequin indicates it backfilled the products table to your stream.

2

Receive messages

Using the Sequin Stream API, let’s receive some messages. Copy the curl command from the “Overview” tab:

In your terminal, run the curl command. You’ll receive a response with a single message from the initial backfill of the products table:

{
  "data": [
    {
      "ack_id": "MTYyeJ7abUjl1pO",
      "record": {
        "id": 1,
        "name": "Avocados (3 pack)",
        "price": 6.99
      },
      "action": "read",
      "metadata": {
        "table_schema": "public",
        "table_name": "products",
        "commit_timestamp": "2024-03-20T15:30:00Z",
        "commit_lsn": 123456789,
        "commit_idx": 1,
        "database_name": "myapp-prod",
        "consumer": {
          "id": "f47ac10b-58cc-4372-a567-0e02b2c3d479",
          "name": "products-stream",
          "annotations": {}
        },
        "database": {
          "id": "12345678-9abc-def0-1234-56789abcdef0",
          "name": "myapp-prod",
          "annotations": {},
          "database": "myapp-prod",
          "hostname": "db.example.com"
        }
      }
    }
  ]
}

If you run the curl command again, you’ll receive a different message. That’s because Sequin Stream only re-delivers messages after the visibility timeout expires.

Messages are flowing from Sequin to your stream.

3

Make some changes

Let’s make some changes to the products table and see them flow to your stream.

In your terminal, run the following command to insert a new row into the products table:

docker exec -i sequin-sequin_postgres-1 \
  psql -U postgres -d sequin_playground -c \
  "insert into products (name, price) values ('Organic Honey (16 oz)', 12.99);"

Receive messages from your stream again to see the new change. This time, include the ?batch_size=10 parameter to receive multiple messages at once, like so:

curl -X GET "http://localhost:7376/api/http_pull_consumers/products_sink/receive?batch_size=10" \
  -H "Authorization: Bearer YOUR_API_TOKEN"

Feel free to try other changes:

Each change will appear in your stream within a few seconds.

You can acknowledge messages to ensure they’re not delivered again:

curl -X POST "http://localhost:7376/api/http_pull_consumers/products_sink/ack" \
  -H "Authorization: Bearer YOUR_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"ack_ids": ["MTYyeJ7abUjl1pO"]}'

Great work!

You’ve successfully:

  • Set up a complete Postgres change data capture pipeline
  • Loaded existing data through a backfill
  • Made changes to the products table
  • Verified changes are flowing to your Sequin Stream

​
Ready to stream

Now you’re ready to connect your own database to Sequin and start streaming changes:

Guide: Connect Postgres

Connect your Postgres database to Sequin.

Guide: Setting up a Sequin Stream sink

Setup a Sequin Stream sink to process changes with exactly-once delivery.