There are a ton of bookmarking software, and good, and self-hosted.
- karakeep
- grimoire
- omnivore
- wallabag
- linkwarden
I myself use RSS reader / bookmark manager that I wrote [1]. Everything is open source. Even data [2] [3].
Links
[1] https://github.com/rumca-js/Django-link-archive
[2] https://github.com/rumca-js/Internet-Places-Database
[3] https://github.com/rumca-js/RSS-Link-Database
Don't forget Readeck. I've been super pleased with it. (Omnivore is dead btw.)
Omnivore is open source, bit weird people insist on open source because 'future proof' and then when the commercial entity disappears, it's 'dead'. Why do people make their own instead of making an entity around what is already there if it was liked and open? Very much a validation for not open sourcing anyway. But then again, I cannot possibly use Obsidian or so because when they sell the place (not if, when), sure I have the open format, but not the nice tooling. I rather struggle with inferior open source products and contribute on those than having to go through these 'Google bought us, you have 2 months to export your data' kind of thing.