Gregory's Server@abcdw Looks interesting.
We have been using Schema and do get similar benefits (already several years). #cljKondo seems to support https://plumatic.github.io/schema/schema.core.html#var-defn from what I gather, as well as basic type hints of #Clojure (I've probably bumped into them in a warning already).
We've mostly used Schema for the API and DB layers so far, but gradual typing for core functions could be nice at this stage of the project.
@Macroz Yep, schema IIRC is the oldest of those three (malli, spec, schema). It's nice and intuitive, but feels a little bit foreign, non-idiomatic, but it's just my perception. I'm a little impressed how good malli feels, it seems it took the best from schema and clojure.spec. Maybe I'll change my mind later, but I'm very satisfied rn :)