The best alternatives to Step CI are RapidAPI, Postman, and Thunder Client. If these 3 options don't work for you, we've listed a few more alternatives below.
Postman is the world’s leading API platform, used by more than 30 million developers and 500,000 organizations worldwide for building and managing APIs.
Postman enables teams to efficiently collaborate at every stage of the API lifecycle while prioritizing quality, performance, and security.
Thunder Client is Rest API Client Extension for Visual Studio Code, with simple and clean design. The extension makes api testing very easy with Scriptless GUI based testing.