AWS SNS has maxReceivesPerSecond setting (for HTTP/S subscriptions) to control how many deliveries per second, per subscription it should do. The problem is that none of the retry attempts follow that limit meaning that if you configure maxReceivesPerSecond to be 1 then as soon as you send 100 messages to the topic then in reality they are sent out within few seconds because 99 messages will be throttled and they end then up being retried and by-passing that limit (made a small test with API gateway where i saw that even if maxReceivesPerSecond was 1 100 requests went through within seconds).