Markdown to Accessible HTML Converter

The Markdown to Accessible HTML Converter turns Markdown into semantic HTML and then applies a layer of accessibility fixes that a plain parser skips. Most converters emit a flat run of headings and paragraphs with no landmarks, no guaranteed top-level heading, and bare <img> tags. This tool produces markup that screen-reader users can navigate.

How it works

1. Parse. A focused Markdown subset is parsed: headings (# to ######), **bold**, _italic_, `inline code`, [links](url), ![images](url), ordered and unordered lists, blockquotes, and fenced code blocks. Inline HTML special characters are escaped.
2. Wrap in a landmark. The whole body is placed inside <main lang="en"> so the primary content is a single, addressable region. Exactly one main per page is the accessibility expectation.
3. Guarantee an h1. If no level-1 heading exists, a visually hidden <h1> is injected so the document has one top-level heading and a sound outline.
4. Promote images to figures. A standalone image line becomes <figure><img><figcaption>…</figcaption></figure>, with the alt text shown as the caption. Images with empty alt are treated as decorative.

Why these transforms matter

The main landmark

WCAG Success Criterion 1.3.6 and ARIA landmark patterns require that the primary content of each page be wrapped in a <main> element so screen-reader users can skip directly to it — bypassing repeated navigation, headers, and sidebars — using their reader’s landmark navigation shortcut. Most plain Markdown parsers output a fragment with no landmarks at all. Without <main>, a user must tab through every navigation link on every page.

The guaranteed h1

Screen-reader users frequently navigate by heading to get an outline of a document before reading it in full. A page with no <h1> lacks a document title in the heading outline, making it harder to understand what the page is about without reading from the top. WCAG Technique H69 and H66 both recommend a descriptive level-1 heading at the start of the main content. The visually hidden injection here provides one structurally without changing the visible design.

Images as figures

When a content image appears in a document, sighted users see both the image and can infer context from surrounding text. Screen-reader users hear only the alt attribute. Promoting content images to <figure> with <figcaption> makes the same caption text visible to everyone and pairs the image with its description structurally. Images with empty alt="" are intentionally left as bare <img> elements — they are decorative and should be skipped by assistive technology.

Before and after comparison

Input Markdown:

![Sales by region](sales-chart.png)

## Q3 Results

Standard converter output:

<img src="sales-chart.png" alt="Sales by region">
<h2>Q3 Results</h2>

Accessible converter output:

<main lang="en">
  <h1 class="visually-hidden">Document</h1>
  <figure>
    <img src="sales-chart.png" alt="Sales by region">
    <figcaption>Sales by region</figcaption>
  </figure>
  <h2>Q3 Results</h2>
</main>

Tips and notes

• Pair the visually-hidden class with CSS (position: absolute; clip: rect(0 0 0 0); …) in your stylesheet so the injected h1 is readable by screen readers but invisible on screen.
• Always write meaningful alt text for content images — this text becomes the figcaption. An alt like “chart” is not descriptive; “Bar chart showing Q3 sales by region, with APAC leading at 42%” gives real context.
• Run the output through the Landmark Region Completeness Checker to confirm the structure matches your full page before shipping.
• The converter handles a focused Markdown subset. Complex tables, footnotes, or raw HTML in the Markdown may need manual review.