Milkman is described as 'JavaFx-based workbench for crafting requests / responses. It is not limited to e.g. http (or more specifically rest) requests but can be extended in any imaginable way. It is optimized for fast startup and efficient workflow' and is an app in the Development category. There are more than 10 alternatives to Milkman for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Chrome OS. The best alternative is Insomnia REST Client, which is both free and Open Source. Other great apps like Milkman are Postman (Freemium), HTTPie (Free, Open Source), Paw (Paid) and Hoppscotch (Free, Open Source).
Postman is a tool that facilitates the development and use of APIs. Postman provides all the functionality needed to create or simulate API specifications and use the Postman Collection Runner to create tests.
Easily craft your HTTP requests, try them, archive them. Setup HTTP Headers, URL parameters, form-encoded POST key-values or text. Get easy-to-read responses with well formatted headers and body. Sync your projects with your team through Paw for Teams.
If you like the interface of HTTPie but miss the features of curl, curlie is what you are searching for. Curlie is a frontend to curl that adds the ease of use of httpie, without compromising on features and performance.