I can't compare to Scala, but unless you know you need an API for a web frontend then I would take a look at tRPC or other "zero API" systems (Blitz is another

I can't compare to Scala, but unless you know you need an API for a web frontend then I would take a look at tRPC or other "zero API" systems (Blitz is another one, but I'm a little unclear on where they are in their pivot). It's a little hard to describe how magical it feels to actually use. It completely removes needing to think about an API. You don't think about endpoints, about (de)serialization, about the mechanics of fetching, or how arguments are passed. You just call you functions by name from the front-end. All your types are preserved so that if you change the signature of your backend function Typescript will catch it everywhere on front-end. If you use react-hook-form then you can export the zod validators that you wrote for the backend and import them to the frontend, and now your client-side code is using the exact same validator as your backend does. Change your server side validation and now your client-side form won't compile and you'll know exactly why. Honestly it feels like the missing link in fullstack dev to me. Typescript brought the types and the compiler, and tRPC makes it feel like your entire back and front-end are one system.