[jonaphin]

As I said, I've used Sails.js. Their ORM is subpar, doesn't even support associations yet. By wrong I meant that where Node.js shines most is in its unified approach to client/server relationships. Since you're building an API (as in server-side logic with world-facing endpoints) you may want to stick to Rails, since it's great at that out-of-the-box, for tried-and-true.

[ricardobeat]

You can't judge the platform by one framework. Node.js also shines in concurrency and networking, which are valuable things for an API, and allows you to offer streaming endpoints with ease.