alt Hacker NewsShow HN: OpenKnowledge – open source AI-first alternative to Obsidian/Notion
Hi HN, Nick here. We’re launching OpenKnowledge (https://openknowledge.ai/), a “what you see is what you get” markdown editor that has direct integrations with Claude, Codex, and other agents. Available as MacOS app or Web UI+CLI. Fully free/local and OSS.
We built this because we wanted a Notion-like experience for writing and sharing markdown files across our team. Obsidian is the best alternative we tried, but found it doesn’t have a true WYSWIG UI and it didn’t integrate well with Claude/Codex outside of community plugins.
So we built OpenKnowledge. It takes shape as:
1. A MacOS app with a file navigator, the WYSIWYG editor, and link explorer.
2. Integrations with the Claude, Codex, and Cursor desktop apps. The agents can open an OpenKnowledge editor within their embedded web browsers for a side-by-side experience.
3. Built-in mcps, skills, and RAG for LLM-wiki and “AI Second Brain” scenarios + spec writing
4. An embedded terminal and CLI for TUI-first users
OSS stack includes: Tiptap/prosemirror, CodeMirror, yjs (CRDT), Electron (MacOS app), Orama, remark/rehype/micromark/mdast, @pierre/trees
On the architecture side, the interesting eng. challenges included:
1. A pipeline to convert ProseMirror to markdown in a bidirectional lossless way. ProseMirror uses ASTs, which are not designed to have byte-fidelity.
2. A dual-observer CRDT to keep the ProseMirror and markdown state in-sync.
The CRDT + git also power a collaborative experience that shows what Agents are doing in the markdown, have undo/redo, and version history. The “Share” and cloud-sync functionality are geared for team collaboration. They feel “no-code” but leverage git/GitHub under the hood, which also means data stays fully private.
In that spirit, we made OpenKnowledge open source for anybody who’s curious or who’d like to contribute.
We’re actively thinking about plugins/extensibility and what’s next. If you have suggestions or feedback, would love to hear it.
Comments
Fully local, but can't integrate with any local LLM?
I do think a fully OSS Obsidian-like that syncs natively is an impressive accomplishment, though the usefulness of this is limited with OSX being the only supported platform. If an Android app is in the works I'll definitely follow the project!
Congratulations on the launch. It looks neat!
On a side note, I find it interesting that a few recent projects are going for the Open Knowledge name. The Open Knowledge Foundation (https://okfn.org) is one of the first/largest proponents of the open data movement (think of it as a Free Software Foundation but for data, not software). They started in 2004 and developed many of the open data licenses and widely used infrastructure tools like CKAN (an open data portal platform).
Nothing to add, just found it interesting.
Disclaimer: I worked there for a few years.
For ages I've been looking for a way to easily share & sync a simple knowledgebase (HTML/MD and other files in folders) with my team (= including non-technical people), using Git as the sync/versioning layer, without it being too technical, and without getting vendor lock-in with expensive & unnecessarily complex cloud-based platforms.
Having built-in AI integration without relying on sketchy plugins would be the cherry on top (although, seriously missing the option to connect with any openai-compatible LLM provider like someone else mentioned here).
Seems like this might almost offer exactly that? I'll have to try it out...
Electron apps tend to fall down in the minutiae of the little things that native apps get right (around things like selection, scrolling, various small affordances across various levels). Would love to see something like this be more native app upfront, than starting out with something that will always leave that top 10% of what makes a nice feeling app unobtainable.
You win hard on this if you have the best possible UX that feels natural to drive. You just also ran if not because obsidian/notion etc. are already there (and have the people to put into those random edge cases that make electron apps bad).
You should just integrate with pi.dev, like I did for https://github.com/rcarmo/piclaw (which has replaced Obsidian for me). I too integrated a terminal and a WYSIWYG Markdown editor (as well as plugins for a mindmap, kanban, etc.)
So it's just a Electron editor + "open in %agent" button... I don't see any reasons to use it instead of. obsidian + my agents.
Is this following the Open Knowledge Format proposed by Google earlier this month or just a name collision?
https://cloud.google.com/blog/products/data-analytics/how-th...
Consider making the first image in the readme either static, or move slowly enough that there's reasonable dwell time to understand the UI when it's done with rendering. Right now there's nowhere on the gif that you can focus on to understand that part of the app in any detail, so it's basically a flashy box of randomness.
I'm working on a PKM myself, and while wysiwyg won't be my first priority and I'm aiming for a more hackable surface, this is very interesting and I'll most likely take inspiration from it for integrating AI workflows into my notes
Nice approach.
Personally I’ve been trying very hard to migrate away from git+Obsidian project setup according to the OpenAI Harness Engineering. It works wonderfully in Codex Desktop.
The only gotcha - I want to share knowledge bases with the team in a way that is:
(1) versioned (a la git, not Notion) (2) usable from any chat (a la MCP) (3) basic access controls for team setup. (4) works through the interface that optimizes accuracy and token use across agentic architectures and LLMs.
Funnily enough, 4 is the easiest one (I have a platform for agent training and verification where I publish fun challenges for agents in simulated worlds around agentic commerce and personal OSes. With 98M agentic interactions recorded, that is already enough information for tuning)
Still figuring 1 and 3, though.
I don't understand how Obsidian, a collection of markdown files, isn't already AI friendly. It's hard for me to imagine a more AI-friendly but still usable way to organize your notes.
The signature figure on the repo shows file contents alongside a chat window. Is this actually supported by the app? I can't figure out how to open a chat window in the app without handing off to an external AI app.
How do you make money, and how will you pay for your salaries?
I've been using my opencode go subscription for Obsidian, saving my Claude sub for actual coding. Any reason why it's limited to Codex, Claude, and Cursor?
Got this toast/notification message from your desktop app.
> Added ok to your PATH — managed block in ~/.zshrc, ~/.config/fish/conf.d/open-knowledge.fish.
Took a while to see that 'ok' is the name of your product.
I'm a sucker for pretty UIs. I already have a company-mandated knowledge base tool, Slite, can they be used together?
Neat, trying it out now. Are the Open Knowledge skills actually needed, if this is just markdown and folders? The skills are large, I'd prefer not filling up context.
Sounds cool. How do agents know what else is going on in the doc? They have an embedded browser and they do like mutation observer type stuff? Or does the integration do polling?
Interesting using tiptap with codemirror, i guess to get around that tiptap doesn’t really support html very well but a shame that we need to use two editors to get the complete experience. Still, nicely done!
Looks powerful. If you focus on notion-like elements you’ll go far. The product roadmap is there—their pricing is nuts.
Is there a migration path from Obsidian or Notion? Switching costs are usually what keeps people locked in.
Just my personal pref with your roadmap, don't waste time on the electron app, I would never use it. A webapp definitely with OpenCode support big on the list as well.
Nothing personal, but there genuinely ought to be consequences for using "open source" in the context of something like this tied to proprietary AI services.
Local models should be the first choice in that framing.
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Nice. the frontmatter question is the one i'd want answered before trusting it: when an agent edits a file does it round-trip YAML frontmatter and nested code fences cleanly, or does that stuff get mangled? every "wysiwyg markdown" tool i've tried falls apart there. Also is the CLI cross-platform or mac-only like the app?
I really wanted to like this, but unfortunately couldn't see how it improves my experience over Obsidian or VS Code.
The fact that I have to juggle between OpenKnowledge and Codex to engage the AI, while also accepting a barebones Obsidian, is a real bummer. From what I can tell, you are saving me a few key strokes with moving prompts around. What I really want is the AI to live IN the app, like VS Code, and then move around the documents like it is Obsidian. I'll accept a plain terminal, but a pretty UI would feel like a better fit. My sense is that the new value add here is a set of skills and mcp servers, which probably already exist for Obsidian, or could more productively be spun up. I looked at the plugins again in Obsidian and found Claudian, which lets me bring my local models and Codex in the right pane. This is perfect, so sorry your app is not for me (yet), but thanks for getting me to look again at my tooling.
I want to throw my vote in for local models. Gemma4-31b is working well for me on these types of tasks, and not having an easy way to plug that in is a deal breaker. Embeddings should certainly have a local option, as they are cheap to compute. For what it is worth, I use LMStudio which supports OpenAI and Anthropic compatible api endpoints, so it should be easy to wire in.
A big caveat, I'm not trying to share my vault with other people, and I can see making that pain go away being worth switching. That said, I feel like you're targeting a weird market, where you want people technical enough to use LLMs and GitHub, but not so technical they can't customize a shared environment.
I would switch if the whole experience was self contained and "clean." Right now, it feels like a well dressed wrapper for pretty basic functionality.