Sinatra is described as 'free and open source software web application library and domain-specific language written in Ruby. It alternative to other Ruby web application frameworks such as Ruby on Rails, Merb, Nitro, Camping, and Rango. It is dependent on the Rack web server interface' and is an app in the Development category. There are six alternatives to Sinatra for a variety of platforms, including Mac, Linux, Windows, Self-Hosted solutions and Ruby. The best alternative is Flask, which is both free and Open Source. Other great apps like Sinatra are Ruby on Rails (Free, Open Source), FastAPI (Free, Open Source), Koa (Free, Open Source) and Pedestal (Free, Open Source).
Expressive middleware for node.js using generators via co to make web applications and APIs more enjoyable to write. Koa's middleware flow in a stack-like manner allowing you to perform actions downstream, then filter and manipulate the response upstream.