> But pure Python is inherently slow because of language design. It also cannot be compiled efficiently unless you introduce constraints into the language, at which point you're tackling a subset thereof. No library can fix this.

A similar point was raised in the other python thread on cpython the other day, and I’m not sure I agree. For sure, it is far from trivial. However, GraalVM has shown us how it can be done for Java with generics. Highover, take the app, compile and run it. The compilation takes care of any literal use of Generics, running the app takes care of initialising classes and memory, instrumentation during runtime can be added to add runtime invocations of generics otherwise missed. Obviously, this takes a lot of details getting it right for it to work. But it can be done.

Very little of what you're claiming is relevant for FastAPI specifically, which in terms of speed isn't too far from an equivalent app written in Go for writing a web app. You need to research the specifics of a problem at hand instead of making broad but situationally incorrect assumptions. The subject here is web apps, and Python is very much a capable language in this niche as of the end of 2025, both in terms of speed, code elegance and support for static typing (FastAPI is fully based on Pydantic) - https://www.techempower.com/benchmarks/#section=test&runid=7...

Implying that existence of your tool of preference in another programming language makes other equally impressive tools something akin to "[colossal] mistake that we'll pay for for years" "simply motivated by inertia" is way below the level of discussion I would expect from Hacker News.