AWS API Gateway can be expensive

As of 2019/11, AWS charges $0.25 per million connection minutes. That sounds very innocent, but is it?

If your business grows and you have up to 1 million devices that needs to keep connected to an AWS Gateway, the cost, every month, just for the connection fee would be:

$0.25*1440*30*1M/1M = $10,800 per month

In this case, a highly available cluster may be a lot more cost effective.