[reducesuffering]

Fast development with reasonable perf will be Typescript and high performance with reasonable dev. will be Go.

If you're absolutely sure you're going to be hammering this API with high scale requirements, then you can spend a bit more time using Go to make a rock solid service. But more likely, you don't know if you'll really need high performance, and using Typescript will have much less context switching between your Next.js frontend.

Personally, just do it in your Next.js /api backend routes.