I noticed that there is a GET that passes a JSON payload:
https://github.com/letsgetrusty/bootcamp/blob/master/4.%20Projects/2.%20API/Problem/Stage%202/Step%202/src/handlers/mod.rs#L56-L68
This is not a recommended practice. In my experience, many frameworks and applications drop sending the payload. Here's a StackOverflow question that supports avoiding GET with payload:
https://stackoverflow.com/questions/978061/http-get-with-request-body