The short comparison
Choose Markdown when writing speed, readable source, portability, and version-control diffs matter most. Choose HTML when the document needs semantics or components that Markdown cannot express, or when you directly own the rendered web page.
| Concern | Markdown | HTML |
|---|---|---|
| Source readability | High for common documents | More markup around content |
| Presentation control | Delegated to renderer | Detailed control with CSS |
| Document vocabulary | Small and opinionated | Broad semantic element set |
| Portability | Strong within common syntax | Strong on the web |
| Interactivity | Usually none | Possible with scripts and components |
| Security surface | Renderer-dependent | Active content requires strict controls |
Where Markdown is stronger
Markdown keeps authors focused on the document's hierarchy and words. A heading is a heading without decisions about class names, spacing tokens, or responsive breakpoints. That makes routine technical writing faster and review diffs calmer.
The tradeoff is that the renderer has the final say. The same table or task list can look different across GitHub, an editor, and a static-site generator, and some extensions may not exist everywhere.
Where HTML is stronger
HTML can represent navigation, figures, details panels, forms, definitions, media, and rich accessibility relationships that core Markdown cannot. Combined with CSS, it supports precise layouts and design systems.
That power adds responsibility. Authors or component systems must produce valid semantics, keyboard-friendly interaction, responsive styling, and a safe content boundary. Raw HTML from an untrusted document must never be injected without sanitization.
Most documentation systems use both
A common pipeline stores articles as Markdown, converts them to HTML, then applies shared components and CSS. Authors get readable source while the website gets navigation, syntax highlighting, responsive layout, and accessibility features.
Some systems allow raw HTML inside Markdown. Use that escape hatch sparingly: it reduces portability and can enlarge the security surface. Prefer a documented component or extension when the publishing platform offers one.
Markdown: ## API reference [Read the schema](/schema) HTML: <h2>API reference</h2> <a href="/schema">Read the schema</a>
Converting HTML to Markdown is intentionally lossy
Semantic headings, paragraphs, links, lists, code, and simple tables usually have clear equivalents. CSS layout, class names, scripts, forms, and custom widgets do not. A good conversion keeps the readable document and leaves the web application behind.
After conversion, inspect relative links, image references, code fences, and any raw fragments. The editor preview should sanitize untrusted output, but publishing still deserves its own content policy.