Rails is, by design, a very opinionated tool. The focus on establishing sensible defaults as a convention is great if you can work at least somewhat within thos

Rails is, by design, a very opinionated tool. The focus on establishing sensible defaults as a convention is great if you can work at least somewhat within those conventions, but it can become increasingly annoying if you regularly bypass the defaults. The goal is to make development easier, but you probably won't gain those benefits if your definition of "sensible defaults" isn't compatible with the choices made by Rails. Sinatra is a very different approach, which may work better if you want minimal library that doesn't involve a set of design conventions. Both Rails and Sinatra are useful tools; use whichever is a better fit for your needs.