Accept orders at any speed, process them at your own, and fan each one out to several systems.
How it works
›SQS standard queues take a very high, nearly unlimited number of requests a second and store each message in several Availability Zones before acknowledging it.
›Delivery is at least once: a message can arrive twice, and one that is not deleted becomes visible again after its visibility timeout (30 seconds by default).
›SNS publishes each message to every subscriber, often one SQS queue each. In us-east-1 an account can publish 30,000 messages a second by default.
›Limits come from AWS documentation (default quotas in us-east-1). Where AWS publishes no figure, such as how many requests a container or database handles, the lab states its assumption on the component.
What you'll build
A direct design at 1,800 orders a second
A queue and workers that absorb a 9,000 per second spike