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 app

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.