[cies]

My experience scaling up Rails (mostly in size of codebase NOT in size of traffic) really made me love typesafe languages.

IDE smartness (auto complete, refactoring), compile error instead of runtime, clear APIs...

Kotlin is a pretty nice "Type-safe Ruby" to me nowadays.

[Alifatisk]

I had a similar experience, working in a large Ruby codebase made me realise how important type-hints is, sometimes I had to investige what types where expected and required because the editor where unable to tell me. I hope RBS / Sorbet solves this.