Logseq - an open source roam research alternative
Note
Roam research is a great application for note-taking using the zettelkasten method, and one of the most popular ones. It has seamless support for backlinking, autocreation of pages (nodes), graph view, etc., everything you would need for a zettelkasten experience.
So why would you look for an alternative? Well, for one, roam research has a paywall, which might put off people who want to just try it out. (There is a free trial for a month, so if that works for you, go ahead!). Also, it does not let you self-host your notes, everything is stored on their cloud. Which is not ideal if you care too much about privacy and longevity of your notes. And it's not open source, which can also be a wall for some people.
What is the alternative, then? I recently discovered Logseq and I would say it's a very promising application, ticking all the boxes from above, as well as being hugely inspired by Roam and supporting a lot of the features already despite being in alpha (which should change soon I believe). What's more, it supports writing notes in org-mode, which was an instant selling point for me as I use Emacs for a lot of my workflow.
Logseq has the option to host notes in a Github repository with automated sync, or a local directory (this requires the Native filesystem API on Chrome so it works only on chromium based browsers, Brave excluded, since it removed support for that API). But Logseq has a desktop application as well, so your setup can be fully local and offline.
For an application in alpha, it's pretty damn impressive. It has a long way to go yet, but i'll be looking at it (and using it) with interest.
Give it a go!