I've been using HTTPie a lot more recently. It really takes the tedium out of using curl and I can produce color coded output for people. However, I am still finding myself in situations where I can't figure out how to induce the correct request. In other words, the user friendliness of being able to do things like construct JSON from parameters is great until it isn't.

Is there anything similar for GUI users? The standalone application form of Postman is popular with some coworkers for general HTTP work as is Fiddler on Windows.