The stand-alone BcfApiExampleClient has been updated now and works again:
https://github.com/rvestvik/BcfApiExampleClient
I adapted the Revit version of it, retested, and it works fine too:
https://github.com/jeremytammik/RvtBcfApiExampleClient
Please also note this comment by Georg Dangl:
https://github.com/rvestvik/BcfApiExampleClient/issues/2
He says: In December we had another Hackathon in Munich where Veni Lillkall created a small sample app in C#:
https://github.com/BIMit/BCF-Hackathon-Munich/tree/Team_C%23
This might give you some ideas how to use the BCF API itself.
Cheers,
Jeremy