I’d like to recommend the app Insomnia, a desktop application for testing HTTP and API endpoints.
Previously, I have used the Chrome app “Postman” but I needed to test non-standard HTTP methods (not supported in Postman).
Support for non-standard HTTP methods
I am using Insomnia to test communication with a Belkin Wemo Switch, which makes use of the SUBSCRIBE method for registering for change notifications. The switch then sends an EVENT method when the state is changed.
Developing my Elixir library for the Wemo Switch has been possible with the help of Insomnia. Postman only supports a fixed list of HTTP methods.
Stand-alone application
It looks like Insomnia is an Electron based application, and it is available for all 3 major desktop platforms — Windows, Linux and OS X. It is free, but you can choose to pay if you want team synchronisation capabilities.
Being a stand-alone application is great, as I no longer need to start up Chrome to then start up Postman. As I am using Chrome less frequently these days, this means one less step.
Finally, Insomnia is open source.