Ask HN: How much load can Next.js API Routes handle?

I don't know how to load test or stress test, so I was wondering if anyone had tried this with Next.JS - i.e. just using it as an API Server.

I know that Next.JS is primarily used to build websites and web apps, and that they have indeed added the Edge API Routes which is custom built for this, but I'm still curious re regular old API Routes, since Edge API Routes are beta, so may get cut in the future. TIA.