rbs_rails VS spylls

I haven't used rbs in the context of rails, but a quick googling leads me to https://github.com/pocke/rbs_rails , which includes some rake tasks to generate rbs files for models. There are also some libs to do the same for protobuf and json-schema (which I haven't tried yet as well).

In my experience of working on complicated algorithmic project (spylls spellchecker) in Python after 15+ years of Ruby, I really liked the gradual typing experience: you write dynamic code to get a grip of the logic, and then start to add typing here and there - and it does help to clarify design, catch accidental null possibility, and in general make inter-module API more visible.

Currently, Spylls has ≈1.5k lines of library code in 14 files. It conforms (with some reservations) to all Hunspell's integrational tests. Those tests look like a set of files each, consisting of "test dictionary + what words should be considered good, what words should be considered bad, what should be suggested instead of the bad words", and there are 127 of such sets to pass. There are 2 thousand comment lines in the code, explaining thoroughly every detail of the algorithm and rendered at the Spylls documentation site; note that besides docstrings at the beginning of each class and method, there are also inline comments in code—that's why the documentation site uses custom theme with inline "Show code" feature.