The best open source alternative to Open-Notebook is Deta Surf. If that doesn't suit you, we've compiled a ranked list of other open source Open-Notebook alternatives to help you find a suitable replacement.
Open-Notebook alternatives are mainly Personal Knowledge Management (PKM) Tools but may also be Web Browsers or Note Taking & Knowledge Management Tools. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Open-Notebook.
A browser that doubles as a personal notebook, letting you research, summarize, and take notes on web pages, PDFs, and videos without switching apps.

Deta Surf is a browser and notebook rolled into one. It's built for people who spend serious time researching online and find themselves constantly juggling tabs, copy-pasting into notes, and losing track of where they found things. Instead of treating browsing and note-taking as separate activities, Surf makes them happen in the same place.
The core idea: your notes and your browsing exist in the same stream. You can pull in websites, PDFs, YouTube videos, and local files directly into a notebook and start asking questions or writing without ever leaving the page. Summaries, deep dives, and interactive graphs can be generated from the content you're looking at. No copy-pasting, no tab-switching.
Key capabilities include:
Surf is designed to be local-first. Your data stays on your device, and you can import or export it freely. On the AI side, you can bring your own API key, connect to the LLM provider of your choice, or run local models entirely offline. That makes it meaningfully different from cloud-locked tools where your research and notes are held on someone else's server.
If you've used tools like Logseq or AnyType for networked note-taking, Surf occupies adjacent territory but adds a full browser layer on top. It's closer to a Comet Browser in spirit, but with a stronger emphasis on building a personal knowledge base from what you browse. The source code is open on GitHub, and the project is actively developed.