A bit of history
Crystal was created in mid 2011 at Manas Technology Solutions (https://manas.tech/), an Argentinian consulting company that worked a lot with creating Ruby on the Rails applications at that time. Ruby is an enjoyable language to work with but has always been questioned for its lacking performance. Crystal came to life when Ary Borenszweig, Brian Cardiff, and Juan Wajnerman started experimenting with the concept of a new language similar to Ruby. It would be a statically typed, safe, and compiled language with pretty much the same elegant syntax as Ruby but taking advantage of global type inference to remove runtime dynamism. Much has changed since then, but these core concepts remain the same.
The result? Today, Crystal is a stable and production-ready, 10-year-old language with over 500 contributors and a growing community. The team behind it successfully implemented a language with a fast concurrent runtime and a unique type inference system that looks at the entire program in one go while retaining Ruby's best features.
The initial motiving factor for the creators was performance. They enjoyed programming in Ruby and using Ruby's vast ecosystem, but the performance wasn't there. Ruby has improved a lot since then, but even today, there is a sensible gap compared to other dynamic languages such as Python or JavaScript.
It began with a simple idea – what if we could have the same expressiveness as Ruby, infer the types of all variables and arguments based on the call sites, and then generate native machine code similar to the C language? They began prototyping it as a side project in 2011, and it worked. Early on, it was adopted as a Manas project, allowing the trio to work on it during paid hours.
Crystal has been developed in the open since its very beginning in a public repository on GitHub at https://github.com/crystal-lang/crystal. It brought a community of users, contributors, and also sponsors banking on Crystal's success. The initial interest came from the Ruby community, but it quickly expanded beyond that. You can see in the following figure the growth in people interested in Crystal, measured by the number of GitHub "stars" on the main repository.
Figure 1.1 – The steady growth of GitHub stars
At the time of writing, the latest version is 1.2.2, and it can be installed from Crystal's official website, at https://crystal-lang.org/.
Much inspiration came from Ruby, but Crystal evolved into a different language. It kept the best pieces of Ruby but changed, improved, and removed some of its legacies. Neither language aim to be compatible with the other.
Understanding this history gives you the perspective to follow what motivated Crystal to be created and to evolve into what it is today. Crystal has grown to be very performant but also very expressive. Now, let's see what empowers this expressiveness.
