I had met Marcel van Lohuizen when he was in the board of my previous company. One of the passionate techie and down to earth guy. He was actually working on cuelang and had not released it yet. After he gave us a presentation on Cue, one of my thoughts was that it is not easy for beginners to grasp it but then the language is not meant for beginners. My Second thought which was completely whack, was may be you could use it as a add-on for Protobufs, as the schema definitions in Cuelang has validations builts into it, which might remove boilerplate validation code in grpc services.