Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
HttpMaster - HttpMaster is a professional software tool for testing and debugging HTTP applications, primarily aimed at REST API applications and web services.
TaskPaper - Plain text to-do lists for Mac
Hoppscotch - Open source API development ecosystem
Listy Beta - The things you love, privately saved and beautifully listed
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.