I have seen FastAPI is being adopted in newer projects like jupyter FPS .
Even though FastAPI is being very popular due to its easy to use flask style api with async (but actual FastAPI async in production have alot of problems and memory leaks , compared to Battle Tested tornado , and author do nothing about PR that sent to fix them). , if you actually checked at the commit log , it was actually unmaintained for almost a year. Almost all “Releases” are just “Promotional” material where the author (or automated bot) push versions after adding a sponsor name , just to promote them.
Further more , the author ignored community contributions , where a lot of production problems are being fixed and pull requests are ignored , which he said something along the line which means he don’t like other people code.
And FastAPI do not even have an actual API documentation
Author do not want into turn FastAPI into community maintained project and it make it very dangerous for enterprise adoption .