I built NervaBrain, an open-source, self-hosted second brain built around a plain Markdown vault.
The idea is simple: I wanted one place for notes, tasks, projects, goals and personal context without moving everything into another proprietary database.
So the vault itself is the source of truth.
You can open the same files with Obsidian, Git or any Markdown editor. NervaBrain adds a web interface and workflows on top of them.
It currently includes:
- notes, inbox, tasks and projects
- daily briefs and weekly reviews
- goals and custom dashboards
- RSS feeds
- a native MCP server
- optional Claude and Codex integrations
AI is completely optional. When enabled, NervaBrain retrieves relevant context from the vault instead of sending the entire knowledge base for every request.
The AI bridge also runs separately with read-only access to the vault, while writes go through the application.
The main design constraint was portability: if NervaBrain disappears tomorrow, your data is still just a folder of readable Markdown files.
It runs with Docker Compose and is licensed under AGPL-3.0.
GitHub:
https://github.com/paulgdl9/nervabrain
Website / docs:
https://nervabrain.com
I'd love feedback on the Markdown-first architecture, especially from people building or self-hosting personal knowledge systems.

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