The registry exposes both a User Interface (UI) for use by humans and an API for computers. Note that if you click on one of the endpoints, you'll get a web page - as the request is coming from a browser the registry is trying to be helpful (or not). To find the actual API endpoint, you need to click one of the options in the navigation tree on the left to get the API details - such as for the search or for downloading a package. Theres also swagger documentation available.
The API interface performs similar functions to the UI, and is intended for application use.
The search API is based on the NPM API rather than FHIR, as the idea of packages comes from NPM as stated in the beginning. It has the following url pattern: https://packages.simplifier.net/catalog?<parameters>.
- name (ie the package name)
The version API will return a list of all the versions for a given package.
If has the format https://packages.simplifier.net/<package-name>
The download API is also based on NPM. Its main purpose is to be able to download a package directly assuming you know the package name and version. (As noted above, you can also use NPM or Firely Terminal (ex Torinox).