If you need an API Gateway that can work with Lambda, but with better performance and feature set, take a look at https://github.com/Mashape/kong - there is an open PR for Lambda support which will land in the next version (I am one of the core committers).
This is very interesting. Especially when you have a large volume of trivial requests, the cost-per-request of AWS API Gateway dominates overall cost (the Lambda functions themselves are cheap by comparison). Rolling one's own in EC2 can potentially be much cheaper.
