OpenKnowledge: An AI-First Open Source Alternative to Obsidian and Notion

OpenKnowledge is an open-source "what you see is what you get" (WYSIWYG) Markdown editor designed as an AI-first alternative to tools like Obsidian and Notion. It provides a seamless writing experience for teams by combining a local-first file structure with direct integrations for leading AI agents, enabling a collaborative "AI Second Brain" for specification writing and knowledge management.

Native AI Agent Integrations

OpenKnowledge differentiates itself from traditional Markdown editors by providing deep, native integrations with Claude, Codex, and Cursor desktop applications. Unlike community plugins found in other tools, these integrations allow AI agents to open an OpenKnowledge editor within their embedded web browsers, creating a side-by-side experience where agents can interact with documents in real-time.

To support these agentic workflows, the platform includes:

• Built-in MCPs and Skills: Specialized capabilities for LLM-wiki scenarios.
• RAG Support: Integrated Retrieval-Augmented Generation to enhance the accuracy of AI-driven knowledge retrieval.
• AI-Driven Collaboration: A system that allows users to see exactly what AI agents are modifying within the Markdown files.

Technical Architecture and Engineering

OpenKnowledge is built on a modern open-source stack designed to solve the conflict between rich text editing and plain-text Markdown fidelity.

The Tech Stack

• Editor Core: Tiptap/ProseMirror and CodeMirror.
• Concurrency: yjs (CRDT) for real-time collaboration and state synchronization.
• App Framework: Electron (currently available as a macOS app).
• Search and Parsing: Orama, remark, rehype, micromark, and mdast.

Engineering Challenges

The development team solved two primary technical hurdles to ensure the tool remains a viable replacement for professional documentation:

1. Lossless Markdown Conversion: The team developed a pipeline to convert ProseMirror ASTs to Markdown bidirectionally without losing byte-fidelity, ensuring that the underlying files remain clean Markdown.
2. Dual-Observer CRDT: To keep the ProseMirror state and the Markdown state in sync, a dual-observer CRDT was implemented. This architecture, combined with Git, enables version history, undo/redo functionality, and collaborative editing.

Team Collaboration and Data Privacy

OpenKnowledge leverages Git and GitHub as its underlying synchronization and versioning layer. This approach allows the tool to feel like a "no-code" experience for non-technical team members while ensuring that data remains private and versioned. By using Git for the backend, OpenKnowledge avoids vendor lock-in associated with proprietary cloud-based knowledge bases.

Community Feedback and Limitations

While the launch has been well-received for its UI and AI-first approach, the Hacker News community highlighted several key areas for improvement and current limitations:

• Platform Availability: The application is currently limited to macOS, with users expressing a strong desire for Windows, Linux, and Android support.
• LLM Flexibility: Users noted that the tool is currently tied to specific proprietary services (Claude, Codex, Cursor). There is significant demand for support for local LLMs and OpenAI-compatible providers to align with the "open source" philosophy.
• Migration Paths: Potential users have questioned the availability of migration paths from established tools like Notion or Obsidian to reduce switching costs.

"For ages I've been looking for a way to easily share & sync a simple knowledgebase... using Git as the sync/versioning layer, without it being too technical, and without getting vendor lock-in... Having built-in AI integration without relying on sketchy plugins would be the cherry on top."

Access and Installation

OpenKnowledge is available as a macOS app and a CLI tool. Upon installation of the desktop app, the tool adds ok to the system PATH via the .zshrc or fish configuration files to enable TUI-first workflows via the embedded terminal.