"Build the backend once" is a silly notion; software is never static; neither the front-end OR the backend. I can appreciate the front-end-first philosophy, an

"Build the backend once" is a silly notion; software is never static; neither the front-end OR the backend. I can appreciate the front-end-first philosophy, and can see it working well in an environment where you what to build something to "show off" (kind of like WordPress templates that you can "demo"). It might even work fine for something like AirBnB in which the bulk of the application is just a CRUD mesh. I cannot see it working well for any startup that relies on technology that requires a careful and thorough iteration of its foundation (backend). Once the backend is built with a solid RESTful interface, it's trivial to write the front-end and you can A/B test the shit out of it, do white-labeling, try different workflows and UX experiments all while only making tweaks or small additions to your backend (of course excluding major deep-feature development).