What I meant to say was that I felt Rails was too rigid for some purposes, especially creating single-page applications. It's true that Rails wasn't built with

What I meant to say was that I felt Rails was too rigid for some purposes, especially creating single-page applications. It's true that Rails wasn't built with that in mind originally, but it seems that it's becoming a bit easier now (I haven't been following Rails lately and had never heard of the "API mode" you mentioned). I also know about a couple of projects using React successfully within Rails apps, but I would personally not do that if I were to start a new project today, even though I love Ruby.