Hey everyone! I've been working on a side project and wanted to share it.
What I built
dontsendfile.com/md2pdf — A free Markdown to PDF converter where your files never leave your browser. Everything runs client-side via WebAssembly. No uploads, no servers touching your data.
Why I built it
Most online converters require you to upload your files to some random server. I wanted a tool where I could convert sensitive docs (meeting notes, internal specs, personal journals) without trusting a third party.
Key features
- 100% browser-based — Powered by WebAssembly, nothing is sent to any server
- LaTeX math equations — Inline and block math rendered via MathJax
- Mermaid diagrams — Flowcharts, sequence diagrams, etc. rendered as SVG
- GitHub repo support — Paste a GitHub URL and convert any .md file directly
- Local folder support — Drop a folder with multiple .md files and images
- Batch export — Select multiple files and export them all at once
- GitHub-flavored Markdown — Tables, code blocks, task lists, and more
The engine behind it: marknest
The core rendering is powered by marknest (https://github.com/developer0hye/marknest), an open-source Markdown-to-HTML renderer I built in Rust, compiled to WebAssembly. It handles Mermaid diagrams, math equations, and theming — all running in the browser with zero server dependency.
Tech stack
- marknest (Rust -> WASM) for Markdown rendering
- Next.js (App Router) for the site
- MathJax & Mermaid.js bundled as client-side runtime assets
Try it
https://dontsendfile.com/md2pdf
Would love your feedback — especially on rendering quality and any Markdown edge cases you run into. Thanks for checking it out!
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