Hariette posted that she thinks #ArtemisApp will be publicly available within a week: https://tech.lgbt/@hariette/110800032271275199
...but with the caveat that right now it will only work for users subscribed to her kbin instance (this is because she has enabled an API which has been in development, and is now undergoing review).
There are others in development too, but full release of the API and roll out of this to kbin.social is key first.