If you like Roam you should also check out LogSeq. I found it to be a better fit for my use case when I was looking for a Roam Research replacement. 🤙
Discussion
API? And can I easily host it on my server and/or from a cloud service location?
There’s also Tana. Great design, but I’ve found it a bit overwhelming.
https://help.tana.inc/getting-started-and-overview/getting-started-for-roam-users.html
I use logseq along with Obsidian, reading from the same database, it's neat.