This guide shows you how to set up Postgres change data capture (CDC) and stream changes to Amazon SNS using Sequin.

With Postgres data streaming to SNS you can fan‑out events to SQS queues, trigger AWS Lambdas, send emails, stream to AWS Kinesis, and more.

By the end of this how‑to, you’ll have database changes flowing into an SNS topic.

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Prerequisites

If you’re self‑hosting Sequin, you’ll need:

  1. Sequin installed
  2. A database connected
  3. An AWS account

If you’re using Sequin Cloud, you’ll need:

  1. A Sequin Cloud account
  2. A database connected
  3. An AWS account

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Basic setup

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Create an SNS topic

If you don’t have a topic already, create one in the SNS console:

  1. Click “Create topic”.
  2. Choose “Standard” unless you need FIFO ordering. Note that FIFO SNS topics can only fan‑out to SQS queues. (Read more about FIFO vs standard topics in the reference.)
  3. Give the topic a name, e.g. postgres-changes.
  4. Click “Create topic”.
  5. Copy the Topic ARN – you’ll need it when configuring the sink.

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Create an IAM user for Sequin

Create an IAM user with permission to publish to the topic:

  1. Open the IAM console.

  2. Click “Users” → “Add users”.

  3. Name the user (e.g. sequin-sns-publisher) and select “Access key – Programmatic access”.

  4. Attach the policy below (replace <your-topic-arn>):

    {
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "sns:Publish",
        "sns:PublishBatch",
        "sns:GetTopicAttributes"
      ],
      "Resource": "<your-topic-arn>"
    }
  ]
}

  5. Finish the wizard and save the Access Key ID and Secret Access Key. You’ll enter these in Sequin next.

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(Optional) Enable retention for changes

You can stream either changes or rows to SNS. Changes are transient; if you need to replay them later consider change retention or streaming a retention table instead.

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Create SNS sink

In Sequin, navigate to the “Sinks” tab, click “Create Sink”, and select “SNS Sink”.

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Configure the source

1

Select source table

Under Source, choose the table you want to stream.

2

Choose message type

Decide whether to receive changes or rows. If unsure, start with Changes.

3

Specify filters

For changes you can restrict to insert, update, and/or delete actions and add SQL filters such as mrr > 100.

4

Specify transforms

Optionally transform the shape of messages using transforms.

5

Specify backfill

Optionally send a backfill of existing rows. Toggle Backfill off if you only need new changes.

6

Specify message grouping

Leave the default grouping (primary key) so events for the same row share a MessageGroupId when using FIFO topics.

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Configure SNS

1

Enter topic details

Fill in:

  • Topic ARN (required): The ARN you copied earlier.
  • AWS Access Key ID / Secret Access Key (required): Credentials you created for Sequin.
2

Test connection

Click “Test Connection” to ensure Sequin can publish to the topic.

3

Create the sink

Give your sink a name, then click “Create SNS Sink”.

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Verify & debug

To verify your sink:

  1. Make changes in the source table.
  2. Watch the message count increase in Sequin’s “Messages” tab.
  3. Check your subscription (email, SQS queue, etc.) – you should receive the events.

If messages aren’t flowing:

  1. In Sequin click the “Messages” tab.
  2. Inspect any failed message to see the AWS error.
  3. Confirm:
    • Credentials are correct and active.
    • IAM policy includes sns:Publish* permissions for the topic.
    • Topic ARN and region are correct.

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Next steps

  • Process the events

    Subscribe an SQS queue or Lambda function to the topic and build your processor. Refer to the SNS sink reference for the exact message shape.

  • Deploy to production

    When you’re ready, see “How to deploy to production”.

  • Advanced configuration

    Explore transforms, filtering, and grouping options in the sink reference.