I have completed a Sinatra project with Ruby. It's important to note that Sinatra is just a gem. It's a library of code that developers wrote to allow us to build lightweight web applications quickly.
Web applications, even simple Sinatra ones, tend to require a certain degree of complexity. For example, your application might have multiple routes, route-handlers, and configurations. To handle this, Sinatra is more commonly used through the Modular Sinatra Pattern (over the classical, single-file app.RB pattern).
In my experience writing endpoints in Sinatra, it took me some time to understand how the views interacted with the controllers and models. I was used to writing SQL and very complex queries however I did not anticipate the complexity of MVC. Breaking my idea down into the simplest example also helped as well building a basic CRUD web application. I'm looking to expand on what I have built thus far with rails. After completing this project I learned that I also should spend more time learning about sessions and params.
Here's a link to my attendance Sinatra project below if you would like to check it out: