HackMD

HackMD operates a web-based, real-time collaborative Markdown editor and knowledge base used by individuals, teams and open-source communities to write, publish and maintain documentation. Core capabilities include simultaneous multi-cursor editing, in-line and page comments with mentions, version history, note templates, folders and permission controls, publishing with permalinks, book mode and slide mode, embeds, and diagram/formula rendering (MathJax, UML, flowcharts, pie and Gantt charts). Notes can be written and read on desktop, tablet or phone, and shared with flexible permissions that control who may view or edit them.

The product integrates with developer workflows through GitHub sync (and GitLab for enterprise customers), a REST API and the hackmd-cli command-line tool, a browser extension (HackMD-it), webhooks, import/export to PDF and Arweave, and an MCP server. The company positions the platform as a shared context layer between human teams and AI agents: notes are stored and served as Markdown and can be retrieved at the same URLs used by people (including via an Accept: text/markdown header), so agent frameworks such as Claude Code, Cursor, GitHub Actions and OpenAI tooling can pull context and push generated drafts back into a workspace for human review. The company states Markdown content uses up to 80% fewer tokens than equivalent HTML and that its API already serves more than 1 million calls.

HackMD has been used as a public collaboration surface by technical and civic communities; for example, during Taiwan's early 2020 COVID-19 mask-shortage response, a developer documented the cost problems of a crowdsourced mask-availability map in a note posted to HackMD, described as a publicly hosted collaboration tool popular with Taiwan's civic tech sector.

Founding story

In 2014, while completing his master's degree, Max Wu sought a secure way to collaborate and document in Markdown and began building what became HackMD. He introduced it to friends, colleagues and online communities over the following years, which brought early traction and the first outside contributions.

Business model

Freemium software-as-a-service. A free tier supports unlimited notes, up to three teammates/invitees, three custom templates, suggest-edit, GitHub integration capped at 20 pushes per month, 400 API calls per month, 10 recent versions and 1MB image uploads. Paid Prime seats add full-text search, 20MB image uploads, PDF export, unlimited invites, versions, GitHub pushes and templates, 20,000 API calls per month and note insights. An Enterprise tier adds role-based access control, SSO (SAML/LDAP/custom), custom domain and homepage, GitLab integration, self-hosting, custom browser-extension server instance, custom payment methods, priority support and a dedicated account manager. A sponsorship program is offered for non-profit organizations.

Per-seat subscriptions billed monthly or annually. Prime is listed at $5 per seat per month when billed annually (shown as $15 per month total for a three-seat team, a 37.5% saving versus monthly), with Enterprise pricing available on request via a demo.

Traction

The company reports approximately 1 million users, 30,000 teams, 7.7 million notes created and users in 170 countries, and states its API serves over 1 million calls. HackMD is cited in press coverage of Taiwan's civic tech community as a popular publicly hosted collaboration tool.

Latest developments

Recent product additions include an MCP server for agent integration, webhooks, note insights, paragraph citations and bookmarks, guided comments, link previews, editing history display, copy-paragraph links and a make-a-copy function. The website's current positioning centers on interoperability with AI coding and agent tools including Claude Code, Cursor, GitHub Actions and OpenAI, with notes retrievable as Markdown through the REST API and CLI.