What Amazon Gets it Right
Six Reasons to Split Front End and Back End code into Two Git Repositories
Let's keep frontend outside of Ruby
The case for separating front and back
Splitting Monolithic Rails Applications
Another good reason to separate the front-end as a separate app from the backend is that front-end developers can evaluate their design by seeing what the pages look like with different datasets. They can use dummy data that conforms to the JSON API. They don't have to wait for the backend developers to complete the development.