In Felt or Atlas, can connect to external API?

I've recently started trying out Felt and Atlas (which seem pretty similar), but something I'be been wondering is if either can connect directly to a public external API, such as iNaturalist's API. Most public APIs need you to make a specific GET request, and return data in a specific JSON format. I'd then want to show the fetched data as a layer of course.

If this isn't possible in one of those GIS applications, is there an alternative that does allow for this sort of fetching of data from an arbitrary public API?