Crystal is a general-purpose, object-oriented programming language, designed and developed by Ary Borenszweig, Juan Wajnerman, Brian Cardiff and more than 300 contributors.With syntax inspired by the language Ruby, it is a compiled language with static type-checking, but specifying the types of variables or method arguments is generally unneeded. Crystal is currently in active development. It is released as free and open-source software under the Apache License version 2.0.