If you need to build an API quickly we just launched https://code.xyz on Thursday. No server provisioning, no routing, nada, just write a JavaScript function, hit deploy, and you have a scalable "serverless" backend. You can deliver any type of content. (We have command line tools available as well, if the web environment doesn't suit all your needs.)
Our company is called StdLib, we're focused on making API development, deployment and management effortless - we're backed by both Slack and Stripe [1].