MMaster Tools
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Markdown to HTML

Convert Markdown to sanitized HTML and download the result as an .html file, optionally wrapped in a full document.

How it works

  1. 1

    Paste or type Markdown in the input area.

  2. 2

    Toggle 'Wrap in full HTML document' if you want a self-contained file with styles included.

  3. 3

    Click Convert to get the sanitized HTML, then copy or download it as output.html.

Questions

What does 'wrap in full document' do?

It adds the <!DOCTYPE html> declaration, a <head> with a <title> and basic CSS, and a <body> tag, so the downloaded file opens correctly in any browser on its own.

Is the HTML safe to use?

The output passes through a sanitizer that strips script tags, on* event handlers, and javascript: URLs before you see it.

Which Markdown syntax is supported?

GitHub Flavored Markdown — headings, paragraphs, bold, italic, code blocks, blockquotes, tables, task-list checkboxes, and strikethrough.

Is my content uploaded anywhere?

No. The conversion runs entirely in your browser; nothing you write is sent to a server.

JSON Formatter

JSON Formatter

Paste compact or messy JSON and get it back neatly indented with your chosen spacing.

JSON Minifier

JSON Minifier

Remove all whitespace and line breaks from a JSON document to shrink it as small as possible.

JSON Validator

JSON Validator

Check whether a JSON string is well-formed, and see the exact line and column of any syntax error.

JSON Beautifier

JSON Beautifier

Reformat JSON with sorted keys and readable indentation for easier reading and diffing.

JSON Tree Viewer

JSON Tree Viewer

Explore a JSON document as an interactive collapsible tree — expand and collapse any node.

XML Formatter

XML Formatter

Pretty-print XML with configurable indentation, preserving attributes, comments, and tag order.

XML Validator

XML Validator

Check XML for well-formedness and report every error with its line and column number.

YAML Formatter

YAML Formatter

Normalize and re-indent YAML, or convert it to JSON, with a configurable indent width.