md-conv

A fast, secure Markdown to PDF and HTML converter built in Rust.

md-conv uses Headless Chrome for pixel-perfect PDF rendering and includes first-class support for Jupyter Notebooks, YAML front matter, custom CSS, and batch processing.

Features

• Markdown to PDF via pooled Chrome instances (5x faster for batches)
• Markdown to HTML with Handlebars templating
• Jupyter Notebook (.ipynb) conversion to both formats
• YAML front matter for per-document configuration
• Custom CSS with automatic sanitization
• Syntax highlighting via syntect
• Automatic Table of Contents generation
• Watch mode for live preview
• Batch processing with concurrent conversion
• stdin/stdout pipeline support
• JSON output for scripting

Requirements

• Rust 1.75 or later
• Chrome, Chromium, or Edge (for PDF generation)

Installation

From source

git clone https://github.com/jsogarro/md-conv.git
cd markdown_converter/md-conv
cargo install --path .

Verify installation

md-conv --help

Quick Start

Convert a Markdown file to PDF:

md-conv document.md

Convert to HTML:

md-conv document.md -f html

Convert a Jupyter notebook:

md-conv analysis.ipynb

Usage

# Single file
md-conv report.md                       # PDF (default)
md-conv report.md -f html               # HTML
md-conv report.md -f pdf,html           # Both formats

# Batch conversion
md-conv docs/*.md -O output/            # All files to output/

# Custom CSS
md-conv report.md --css styles.css

# Explicit output path
md-conv report.md -o final-report.pdf

# Pipeline
cat input.md | md-conv --stdin -f html --stdout > output.html

# Watch mode (re-converts on file changes)
md-conv report.md --watch

# JSON output for scripting
md-conv report.md -f html --json

# Verbose logging
md-conv report.md -vvv

Front Matter

Control rendering per-document with YAML front matter:

---
title: "Quarterly Report"
author: "Jane Smith"
date: "2026-01-15"
css: "./styles/report.css"
highlight_theme: "base16-ocean.dark"
pdf_options:
  format: "A4"
  margin: "20mm"
  landscape: false
  print_background: true
  scale: 1.0
---

Library Usage

md-conv can be used as a Rust library. Add to your Cargo.toml:

[dependencies]
md-conv = "0.1"

Parse markdown

use md_conv::parser::parse_front_matter;

let markdown = "---\ntitle: My Doc\n---\n# Hello\n\nWorld";
let (front_matter, body) = parse_front_matter(markdown).unwrap();
assert_eq!(front_matter.title.as_deref(), Some("My Doc"));

Sanitize CSS

use md_conv::security::sanitize_css;

let safe = sanitize_css("body { color: red; }").unwrap();

// Dangerous CSS is rejected
let result = sanitize_css("body { background: url('javascript:alert(1)') }");
assert!(result.is_err());

Full conversion

use md_conv::{Args, run};

#[tokio::main]
async fn main() -> Result<(), md_conv::ConversionError> {
    let args = Args {
        input: vec!["report.md".into()],
        ..Args::default()
    };
    run(args).await
}

API documentation: docs.rs/md-conv

Security

md-conv is designed to handle untrusted input safely:

• CSS sanitization -- lightningcss-based parsing blocks javascript:, data:, blob:, file: URLs and @import rules. Defense-in-depth with post-serialization scanning.
• HTML sanitization -- ammonia strips XSS vectors (script tags, event handlers, iframes) from rendered output.
• TOCTOU-safe paths -- Platform-specific file descriptor resolution (fcntl on macOS, /proc/self/fd on Linux, Win32 API on Windows) prevents symlink race conditions.
• Content Security Policy -- CSP meta tags in HTML output.
• File size limits -- Configurable via --max-file-size (default 10MB).
• Timeouts -- PDF generation timeout via --timeout (default 30s).

Exit Codes

Code	Meaning
0	Success
1	General error
2	I/O error
3	Markdown parse error
4	Configuration error
5	Security violation
6	Template rendering error
7	Browser/Chrome error
8	Notebook parse error

Project Structure

markdown_converter/
  md-conv/           # Rust crate (CLI + library)
    src/
      cli.rs         # Command-line argument parsing
      config.rs      # Configuration merging (CLI + front matter + config file)
      error.rs       # Typed error variants with exit codes
      lib.rs         # Core conversion pipeline
      parser.rs      # Markdown and notebook parsing
      template.rs    # Handlebars HTML templating
      renderer/
        browser.rs   # Chrome browser pool management
        html.rs      # HTML renderer
        pdf.rs       # PDF renderer via Headless Chrome
      security/
        css.rs       # CSS sanitization
        path.rs      # Path validation
        toctou.rs    # TOCTOU-safe file operations
    examples/        # Runnable example programs
    tests/           # Integration test suite

License

MIT