Just a note that people interested in this solution should really take a look at Ruby on Jets as it lets you run an essentially standard, drop-in replacement fo

Just a note that people interested in this solution should really take a look at Ruby on Jets as it lets you run an essentially standard, drop-in replacement for Rails on lambda, and the performance seems to be better as well in terms of time to first byte, request latency, etc. We have a 0.995 appdex score running 100% on Jets. Right now we are single region but this could easily be set up in AWS to exist in every AWS edge location and use latency based routing to map to the proper API gateway. Database-wise you're free to tackle that how you like -- no limitations on that end.