Hi Richard! Transitioning to gRPC was a greenfield initiative for us. It took a bit to get the entire organization to switch over, but now it's becoming the default. You can read more about it here: https://elixir-lang.org/blog/2020/06/23/growing-with-elixir-at-brex/

As for the schema validator -- I know it can seem like overkill. IIRC, one of the reasons we used it was to make sure that certain fields that shouldn't have default/empty data were indeed populated in production.