AWS SNS sink

The SNS sink publishes messages to an Amazon SNS topic.

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Configuration

• Topic ARN

  The ARN of your SNS topic. Must match the pattern arn:aws:sns:<region>:<account-id>:<topic-name>.

  For FIFO topics the topic name must end with .fifo.

• Access Key ID

  AWS access key ID that has permission to publish to the topic.

• Secret Access Key

  The secret access key that pairs with the access key ID.

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IAM user permissions

Sequin needs an IAM user or role with the following permissions:

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

Replace <your-topic-arn> with the ARN of your SNS topic (e.g., arn:aws:sns:us-east-1:123456789012:products-updates).

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Message format

By default, Sequin publishes JSON‑encoded messages. You can configure transforms to customize the message format.

When the topic is FIFO, Sequin additionally sets the following per‑entry attributes:

• MessageGroupId – By default the primary key(s) of the source row, or your custom message grouping when configured.
• MessageDeduplicationId – The message’s unique message_id.

This ensures ordered, exactly‑once processing within each group.

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Retry behavior

If Sequin receives an error from SNS, it retries message delivery indefinitely, using exponential backoff with a maximum delay of roughly 3 minutes per attempt.

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Message size limits

SNS enforces a maximum message size of 256 KB.

If SNS rejects a message for exceeding this limit, Sequin cancels that message’s delivery.

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FIFO vs standard topics

Standard topics deliver messages at‑least‑once and may reorder them. FIFO topics guarantee exactly‑once delivery per subscription and preserve the order of messages that share the same MessageGroupId. However, FIFO SNS topics can only send messages to SQS queues.

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When to use SNS vs SQS

Sequin supports streaming to either SNS or SQS directly.

Use Sequin’s SQS sink if you’re sending data to a single SQS queue. Use Sequin’s SNS sink with SQS subscriptions if you need to fan‑out events to multiple SQS queues.

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Debugging

You can monitor the status of your SNS sink in the Sequin console.

On the Messages tab you will see messages currently in flight to SNS, messages that have failed delivery, and recently delivered messages.

Click on any failed message to inspect the full error returned by AWS.

Common things to check when debugging:

• Access key and secret are valid and not expired.
• IAM user/role has the required SNS permissions.
• Topic ARN is correct and the topic exists.
• Region in the sink configuration matches the topic’s region.