Assuming you want to expose a set of APIs, each corresponding to a single function, each API is a separate docker container? What are the performance ramifications of functions-in-docker?
And for the those cases, where it is a big deal, the next two major milestones on the roadmap aim to work around that issue, namely hot containers and streaming input. https://github.com/iron-io/functions#roadmap . Once that's in place, it should perform similar to any API.
