Hi and thanks for your reply!
The authentication is not the problem. I’ve autenticated successfully using the bearer token in the v2 format as described in this post.
I am simply not sure where to send my (I suppose) PUT request, to what endpoint. So i can for example perform a GET request to get a list of all the devices here:
http://<HOMEY_IP>/api/manager/devices/device/
and get a list of all flows here:
http://<HOMEY_IP>/api/manager/flow/flow/.
This is straightforward. But I am not sure how to craft a createFlow action over pure HTTP since http://<HOMEY_IP>/api/manager/flow/createFlow/ for example gives me a 404. When I found out how to do so, I’ll just make a copy of my current flows to ensure I have all the triggers etc in place before starting to substitute parts and make it more dynamic.
Yes, I have successfully created flows using the playground.
Oh, and happy birthday @Dijker! 
