# Hubble Hubble is a free, open source notetaking app built on [[Markdown]] and HTML, by Ben Holmes (`@bholmesdev`). [[MIT License]], TypeScript, [[Electron]], desktop-first. Plenty of apps store notes as Markdown. This one treats a coding agent as a first-class writer alongside you, and builds the app around that assumption instead of bolting it on afterwards. ## Three claims **Feels familiar.** The writing experience is Notion-shaped: `/` commands, Markdown shortcuts, frontmatter as file properties. Built on Tiptap with Markdown conversion underneath. The bet is that most people don't want a Markdown editor, they want the [[Notion]] editing feel with Markdown files on disk. **Agent ready.** Point your agent at the notes folder and start working. Hubble live-reloads as the agent edits. No plugin, no API, no sync protocol; the folder is the interface and the app just stops fighting you about it. **Build any view.** Past plain Markdown you can build HTML-based apps inside your notes. Install the companion skills, tell your coding agent what you want, and a folder of notes becomes a table, a bookshelf, a map, whatever. The runtime for those apps and embeds ships as its own package. ## What's actually there A pnpm monorepo. The desktop [[Electron]] app is the real product; there's an Astro landing page, and a React plus Convex browser version marked *heavily WIP*. Packages split out a framework-agnostic editor core, shared UI, the HTML-app runtime, a filesystem sync engine (also *heavily WIP*), a Convex sync backend for cloud sync, and a `hubble` CLI for syncing a folder from the terminal. macOS, Windows and Linux builds. macOS is signed and notarised; the other two aren't, so expect an OS warning on first launch. First commit February 2026, still moving. ## The repo runs on agents too Hubble's repository automation runs on Warp Factory agents: new issues get triaged with a readiness label and an explanation, anything labelled `ready-to-implement` gets a draft pull request, and every PR gets an agent code review before a human sees it. ## References - Website: https://hubble.md - Source code: https://github.com/bholmesdev/hubble.md - Skills: https://github.com/bholmesdev/hubble-skills - Hacker News discussion: https://news.ycombinator.com/item?id=49091730 - Maker: [Ben Holmes (@bholmesdev)](https://twitter.com/bholmesdev) ## Related - [[Obsidian]] - [[Obsidian Starter Kit]] - [[Markdown]] - [[Notion]] - [[Logseq]] - [[AI Agent Skills]] - [[Claude Code]] - [[Electron]] - [[TypeScript]] - [[Open Source]] - [[MIT License]]