# Markdown Extensions — Going Beyond Plain Text

> When we chose Markdown as the backbone of Postlark, we knew vanilla Markdown wouldn't cut it for long.

- URL: https://engineering.postlark.ai/06-markdown-extensions
- Blog: Postlark Engineering Blog
- Date: 2026-03-31
- Updated: 2026-04-01
- Tags: building-postlark, markdown, developer-experience, mermaid, katex, code-blocks

## Outline

- #GFM as the Foundation
- #The Ten-Extension Drop
- #Keeping Three Renderers in Sync
- #YouTube Embeds
- #What We Chose Not to Build
- #The Dark Mode Tax
- #Where Things Stand