I built a browser-based Markdown Previewer with KaTeX, Mermaid and PDF export

Hey everyone,

I've been building Run It Free — a collection of privacy-focused online tools.

One tool I recently launched is a Markdown Previewer designed to make writing technical content easier.

Features:

• Live split-screen preview

• GitHub Flavored Markdown

• KaTeX math support

• Mermaid diagrams

• Export to PDF / .md

• Syntax highlighting

• Zen writing mode

• Browser-only processing (no uploads)

The goal wasn't to replace IDEs but to create a lightweight editor that opens instantly and works everywhere.

Would love feedback:

What would make you switch from your current Markdown workflow?

Missing features?

UI improvements?

Tool:

runitfree.online

Thanks!