Shameless plug, we've built hurl [1] to add some syntactic sugar over curl, with plain text. For example, you can write a text file post.hurl:

    POST https://api.ctl.io/v2/authentication/login
    {
      "username": "YOUR.USERNAME",
      "password": "YOUR.PASSWORD"
    }

and it will send the same POST request with a json body:

   hurl post.hurl

You can add asserts on the response too:

    POST https://api.ctl.io/v2/authentication/login
    {
      "username": "YOUR.USERNAME",
      "password": "YOUR.PASSWORD"
    }
    HTTP/1.0 200
    [Asserts]
    jsonpath "$.status" == "LOGGED"

Under the hood, we use libcurl and a Rust binding. The HTTP engine is curl because curl is awesome!

[1] https://github.com/Orange-OpenSource/hurl