Are SNS messages fanned out to SQS queues keeping the order?

Question

The AWS FAQs for SNS says:

Q: Will messages be delivered to me in the exact order they were published?

The Amazon SNS service will attempt to deliver messages from the publisher in the order they were published into the topic. However, network issues could potentially result in out-of-order messages at the subscriber end.

Does it apply to SQS consumers, specially a FIFO SQS? I have a use case where one of the consumers needs to maintain the order in which the messages were sent. If this is not the case, I would need to use something else.

Answer 1

Amazon SNS does not currently support delivering messages to SQS FIFO queues. This is documented here.

Important

Amazon SNS isn't currently compatible with FIFO queues.

So since SNS does not guarantee order, and regular SQS queues do not guarantee order, you have no guarantee of message delivery order when using SNS to fan out messages to SQS.

Answer 2

As of yesterday, SNS also supports strict message ordering and deduplication with FIFO topics.

https://aws.amazon.com/about-aws/whats-new/2020/10/amazon-sns-introduces-fifo-topics-with-strict-ordering-and-deduplication-of-messages/