OpenMarkdown

OpenMarkdown is a local-first Markdown editor that stores every note as a plain .md file on your disk with no database or lock-in. The page describes a native Rust core with fast startup (under one second, P50 cold start of 0.2s to click-to-window according to the page). It positions itself as a workspace where you and an AI agent you already have (such as Claude Code, Codex, Gemini CLI, GitHub Copilot, Cursor, or any MCP client) can read, find, write, and co-edit the same document. The page states no AI ships inside OpenMarkdown, that it has no account requirement and no telemetry, and that it offers live preview, source, and reading modes, a command palette, and a trilingual UI. Downloads are listed for macOS (universal, signed and notarized), Windows (x64, note-only, with agent co-editing coming soon), and Linux (AppImage, x64). Agent co-editing is stated to run on macOS and Linux today.

Key features

• Plain .md files stored locally with no database or lock-in
• Native Rust core with fast startup, described as under one second
• Agent co-editing in a sidebar terminal (macOS and Linux)
• Agent can find, read, and write sections of the open document
• Select a passage and ask the agent to rework it in place
• Live preview, source, and reading view modes
• Command palette (cmd+p) for files, headings, and commands
• Autosave on pause and restore of tabs, folder, and cursor after a crash
• Byte-for-byte preservation of file contents
• Deletes move files to the system Trash
• openmd CLI for opening files from the terminal
• Prompt editing via $EDITOR using a prompt.md file
• Connects to any MCP client
• Full trilingual UI (Chinese, Japanese, English)

Best suited for

• Writers and note-takers who want plain Markdown files they control
• Developers and teams who work with AI coding agents on documents such as plans, launch checklists, or prompts
• Users who want local-first editing with no account or telemetry
• Users on macOS or Linux who want agent co-editing

Pricing

Free according to the page ("It's free, and it stays free"), with an optional support/donation option; no paid tiers are described.