lemmy_api_common
This crate provides all the data types which are necessary to build a client for Lemmy. You can use them with the HTTP client of your choice.
Here is an example using reqwest:
let params = GetPosts ;
let client = new;
let response = client
.get
.query
.send
.await?;
let json = response..await.unwrap;
print!;
As you can see, each API endpoint needs a parameter type ( GetPosts), path (/post/list) and response type (GetPostsResponse). You can find the paths and parameter types from this file. For the response types you need to look through the crates lemmy_api and lemmy_api_crud for the place where Perform/PerformCrud is implemented for the parameter type. The response type is specified as a type parameter on the trait.
For a real example of a Lemmy API client, look at lemmyBB.
Lemmy also provides a websocket API. You can find the full websocket code in this file.