HTML to Markdown Converter API

Content

Free HTML to Markdown converter with full formatting control. Transform web content for blogs, documentation, and more.

Authentication

All API requests require a valid API key passed in the Authorization header as a Bearer token.

Rate Limit

100 requests per minute

Endpoints

1 endpoint available

Overview

The HTML to Markdown Converter API transforms HTML content into clean Markdown with extensive formatting options using the Turndown library.

Features

Convert HTML to clean, readable Markdown
Configurable heading styles (ATX or Setext)
Customizable list markers, code block styles, and delimiters
Control link formatting (inline or referenced)

Use Cases

Migrate web content to Markdown-based CMS platforms
Convert HTML documentation for GitHub repositories
Extract content from web pages in portable format
Integrate HTML-to-Markdown conversion in content pipelines

Endpoints

POST

/v1/tools/html-to-markdown

Convert HTML content to Markdown

Request Body

Content-Type: application/json

Parameter	Type	Required	Description
html	string	Required	The HTML content to convert
options	object	Optional	Conversion options
options.headingStyle	string	Optional	Heading format: "setext" (default, underline style) or "atx" (# style)
options.hr	string	Optional	Horizontal rule string (default: "* * *")
options.bulletListMarker	string	Optional	List marker: "*" (default), "-", or "+"
options.codeBlockStyle	string	Optional	Code block style: "indented" (default) or "fenced"
options.fence	string	Optional	Fence style: "```" (default) or "~~~"
options.emDelimiter	string	Optional	Emphasis delimiter: "_" (default) or "*"
options.strongDelimiter	string	Optional	Strong delimiter: "**" (default) or "__"
options.linkStyle	string	Optional	Link style: "inlined" (default) or "referenced"
options.linkReferenceStyle	string	Optional	Reference style: "full" (default), "collapsed", or "shortcut"

Response Example

{
  "success": true,
  "data": {
    "markdown": "# Hello World\n\nThis is **bold** and _italic_ text.\n\n* List item 1\n* List item 2\n\n[Link](https://example.com)",
    "inputLength": 156,
    "outputLength": 98
  }
}

Error Codes

400

Bad Request - Missing HTML content

401

Unauthorized - Invalid or missing API key

429

Too Many Requests - Rate limit exceeded

500

Internal Server Error

Code Examples

curl -X POST https://api.opentools.ca/v1/tools/html-to-markdown \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "html": "<h1>Hello World</h1><p>This is <strong>bold</strong> and <em>italic</em> text.</p><ul><li>List item 1</li><li>List item 2</li></ul>",
    "options": {
      "headingStyle": "atx",
      "bulletListMarker": "-",
      "codeBlockStyle": "fenced"
    }
  }'

Ready to get started?

Create an API key to start using the HTML to Markdown Converter API.