Markdown Editor & Previewer

About the Markdown Editor & Previewer

Markdown is the quiet workhorse of the modern web — it powers README files, GitHub issues, documentation, notes apps, static sites, and chat. But raw Markdown is hard to proofread, and you don't always have an editor handy that renders it. This tool is that editor: write, paste, or drop a .md file and watch it turn into clean, formatted output as you type.

Everything runs in your browser. Your document is parsed and rendered locally and is never uploaded — which matters for unpublished docs, internal notes, and anything you'd rather not paste into a random site.

Three ways in, two ways out

• Drop a file — drag a .md or .markdown file onto the editor and it loads instantly.
• Paste your Markdown — drop in code from anywhere and see it rendered immediately.
• Write from scratch — type in the editor with the preview updating live beside it.
• Download as Markdown — save your .md back to disk at any time.
• Download as HTML — export a self-contained, nicely styled HTML page you can open or share anywhere.

What it supports

• Headings, bold, italic, ~~strikethrough~~, links, and images.
• Ordered, unordered, and task lists (checkboxes).
• Inline code and fenced code blocks.
• Blockquotes, horizontal rules, and tables (GitHub-flavored Markdown).
• Mermaid diagrams — flowcharts, sequence diagrams, Gantt charts, pie charts and more, written as code.
• Switch between split view, editor-only, and a clean reading preview.

Diagrams from code (Mermaid)

Need a flowchart in your README without firing up a drawing app? Drop a mermaid fenced code block into your Markdown and it renders as a live diagram right in the preview:

• Open a fence with ```mermaid, write the diagram, and close it with ```.
• Supports flowcharts (flowchart LR), sequence diagrams, Gantt charts, class and state diagrams, pie charts, and more.
• Diagrams render the same way GitHub, GitLab, and Notion render them, so your file stays portable.
• Download as HTML and the rendered diagram travels with the file — no internet needed to view it.

The diagram engine is loaded only the first time a diagram appears, so the editor stays fast for plain Markdown.

Good to know

• The preview is rendered with the open-source marked parser and sanitized with DOMPurify, so pasted content can't run scripts. Diagrams are drawn with Mermaid in its strict, sandboxed mode.
• The exported HTML embeds its own styling, so it looks the same wherever you open it — no internet required.
• Use Copy HTML to grab the rendered HTML source for pasting into a CMS or email.

No account, no upload — write, preview, download.

Common questions

How do I preview Markdown as I write it?

Type or paste on the left and the rendered result updates live on the right, so tables, nested lists, links, and code blocks come out correct the first time instead of after three commits.

Does it render Mermaid diagrams?

Yes, which most quick editors skip: flowcharts, sequence diagrams, and other Mermaid blocks render right in the preview, exactly as GitHub will show them.

Can I open an existing Markdown file?

Yes. Drop in a .md file, edit with the live preview, and download the result. Round-tripping a README takes seconds.

What Markdown syntax is supported?

The standard set writers actually use: headings, emphasis, links, images, tables, task lists, blockquotes, and fenced code blocks, plus Mermaid. If GitHub renders it, the preview should too.

Is my writing stored anywhere?

No. The editor runs in your browser and your text never leaves it: internal docs stay internal.

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