Welcome to Dev.to! Sinatra is a simple and well-proven framework to learn and I would HIGHLY recommend adding it to your Ruby toolbox. I use it quite often to develop rock-solid web services quickly in Ruby. I notice you called Ruby "old". Well, Ruby may be older than some other "modern" languages but it is stable and solid and THAT is what clients want. In my 35 years of developing software, I have only used about 5 languages regularly and seen many come and go. Ruby is not going anywhere. Each language has its own strengths and weaknesses and excels in specific circumstances. When a language becomes "mature" like Ruby, you don't get hardly any "gotchas" like you do in new buggy languages. So don't fall for the "it's newer so it has to be a better" argument. It's rarely true.
Good luck to you!
Will keep that in mind. Thanks for your time
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.