milkdown

Milkdown is a framework for embedding a WYSIWYG markdown editor into your product. Built on ProseMirror (the same engine behind Notion and Atlassian) and Remark for the markdown parsing. MIT licensed. TypeScript-native. Closest competitor is TipTap, which is built on the same ProseMirror foundation.

This is a library, not an end-user app. You install it via npm, pick the adapter for your framework (React, Vue, Svelte, vanilla), and wire it into your component tree. Plugin architecture lets you add slash commands, math, diagrams, mentions, and collaborative editing through Yjs. GitHub Flavored Markdown support out of the box. The output is real markdown, not a custom format.

If you are building a notes app, a CMS authoring surface, a wiki, or a comment box that needs rich text without HTML, this is the choice. Solo and team size do not matter, the cost is the integration time.

The catch is that you are integrating, not installing. Budget a few days to wire up the plugins you need and another few to style it to match your design system. The plugin ecosystem is solid but smaller than TipTap's. If you need the broadest plugin library and do not mind their licensing model, TipTap is the alternative.