Jester is a good way to go about it.
If you're looking for additional inspiration, you can take a look at how litestore does it: https://github.com/h3rald/litestore
Basically it uses asynchttpserver directly. (I am not related to the project)
I'm working on JSON REST API only using nest as the router.
It's written there query string parameter capture but I didn't find the example for it, since I'm faithfully using asynchttpserver , I just process the query from Request type given.
It's better to use Jester or Rosencratz, but in my case, I find easier to work with vanilla Nim.
I'm going to build another service, but this time I'll have others members to join, and none of them heard/used Nim so I have to accommodate it :(