Let's start with the result to pike your interest. Here is a screenshot.

You can also see it in action here

Please note that this is work in progress, it will change in the coming days and weeks. This is just a peek preview.

If you do not know what this is, it is a UI for an OpenAPI specification. Somehow IMHO OpenAPI and the related Swagger is getting worse rather than better over the years, but it is still incredible and irreplaceable because of the tooling surrounding it.

One of the main tooling is of course this interactive documentation to experiment with APIs directly by sending requests and watching responses. What I find a pity though is that Swagger UI, the default UI and father of OpenAPI, does not look as good as in its early versions. However, fear not, there are plenty of alternatives. The one I favor, which is depicted in the screenshot, is RapiDoc. Try it out, it's good!

Besides of this, OpenAPI has lots of other very practical tooling. It can be used to generate client libraries in various programming languages, or to be imported in various third party tools, ranging from testing tools to integration platforms.