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arenasbob2024-cell
arenasbob2024-cell

Posted on • Originally published at viadreams.cc

Markdown to HTML in 2026: Libraries, Security, and Performance

#markdown #javascript #python #webdev

Markdown is the lingua franca of developer documentation. But when it hits the browser, it needs to become HTML. Here's how to do it safely and efficiently in 2026.

Quick Conversion

JavaScript (marked) 

import { marked } from 'marked';
const html = marked('# Hello **World**');
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Python 

import markdown
html = markdown.markdown(text, extensions=['tables', 'fenced_code'])
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Command Line 

pandoc README.md -o output.html
pandoc -f gfm README.md -o output.html --standalone
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JavaScript Library Comparison

Library Size Speed GFM Extensible
marked 32KB Very fast Yes Moderate
markdown-it 75KB Fast Plugin Very
remark Varies Fast Plugin Extremely

My pick: marked for simple use, remark for AST manipulation.

Markdown Flavors Matter

CommonMark — The strict specification

GFM — Adds tables, strikethrough, task lists

MDX — Markdown + React components

Security: Always Sanitize

Raw Markdown can contain XSS:

<img src="x" onerror="alert('XSS')">
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Always sanitize the HTML output:

import DOMPurify from 'dompurify';
const safeHtml = DOMPurify.sanitize(marked(userInput));
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Try It Online

Convert Markdown to HTML with live preview using DevToolBox's Markdown Preview — GFM support, syntax highlighting, export.

What Markdown library do you use? Share below!

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