HackMD.io is an open source, collaborative Markdown editor. It allows people to share, comment, and collaborate on documents. As open source software, users can choose between using the online platform or installing it as a local service using the upstream project CodiMD.

HackMD's primary feature is obviously the text editor; it leverages the Markdown language, provides handy tools like inserting checkboxes and horizontal separator lines, and allows users to visualize the Markdown rendering while they're working on a document. But HackMD's real power is in enabling collaboration. Let's have a closer look at those features.

Editing collaboratively

Collaborative editing enables more than one person to edit a file at the same time. This is great when, for example, you are running a meeting and want attendees to be able to edit the agenda and the minutes. It can also be used for design documents or brainstorming sessions.

Using collaborative editing is quite simple; you only need to create a new document and share its link with collaborators. You can easily see how many people are online and collaborating on the document.

HackMD also lets you manage document permissions so you can control who has access to your document and who can edit it.

Reviewing a document

Sometimes you need someone just to review a document—not to edit the content but to be able to provide feedback via comments. HackMD supports this use by allowing users to leave comments using the speech bubble symbol.

Clicking the speech bubble lets reviewers add a comment or reply to previous comments.

Exporting a document

Another great benefit of using HackMD as a collaborative tool is that it is easy to export documents or notes in Markdown format. Once a document is exported, you can add it to a Git repository and leverage the fact that most Git hosting platforms support rendering Markdown.

For example, a project's documentation can be written and edited collaboratively in HackMD, then exported and committed to the project's Git repository. This also enables you to use Git to version-control your documentation.

If you are looking for ways to improve collaboration in your open source community, HackMD.io is a great option.