A company wants to create a payment processing application. The application must run when a payment record arrives in an existing Amazon S3 bucket. The application must process each payment record…

Amazon EventBridge also offers at-least-once delivery and requires idempotency in the Lambda function for 'exactly once' processing, similar to SNS, but SNS is a direct and common fan-out destination for S3 events.

Configuring S3 to send object creation events to an Amazon Simple Notification Service (Amazon SNS) topic ensures durable event delivery that can trigger a subscribed Lambda function. While SNS provides at-least-once delivery, an appropriately designed Lambda function implementing idempotency can ensure each payment record is processed effectively 'exactly once' at the application level.

Sending S3 events to an Amazon SQS queue also requires idempotency in the Lambda function to achieve 'exactly once' processing, and while robust for message retention and retries, SNS is a common fan-out pattern for S3 to multiple targets.

Configuring S3 to invoke a Lambda function directly also provides at-least-once delivery, requiring the Lambda function to implement idempotency for 'exactly once' processing, and lacks the fan-out or buffering capabilities of SNS or SQS.