I used rocket (https://rocket.rs) mostly because at the time (Nov '19) it seemed to be the one with by far the best documentation. I think that these days, I would probably go with actix (https://github.com/actix/actix-web), because rocket does not appear to me as being actively maintained and not having async support (yet? there is a branch..) means I need workarounds to integrate with libraries that are async only.

But still, rocket is pretty great. Implementing an endpoint is as simple as a few lines and great integration with serde as well as diesel means you can integrate pretty quickly.