How to use the rvben/rumdl project to lint markdown in Sublime Text

To use rumdl (a high-performance Rust-based Markdown linter) with Sublime Text, you’ll need to set it up as an external “Build System” or integrate it via the SublimeLinter framework.

Since rumdl is a newer tool inspired by the speed of ruff, there isn’t a dedicated “one-click” Sublime package for it yet (unlike VS Code or Obsidian). However, it’s very easy to hook up manually.

Install the rumdl Binary

Before Sublime can use it, the tool must be installed on your system path.

Via Cargo (Recommended): cargo install rumdl
Via Homebrew (macOS): brew install rumdl
Via npm: npm install -g rumdl

Verify it works by running rumdl --version in your terminal.

The Build System Way

This allows you to press Cmd+B (macOS) or Ctrl+B (Windows) to lint your current Markdown file and see errors in a panel.

Open Sublime Text and go to Tools > Build System > New Build System…
Paste the following configuration:

{
  "shell_cmd": "rumdl check --disable MD013,MD033 \"$file\"",
  "file_regex": "([^/\\n]+):(\\d+):(\\d+):",
  "selector": "text.html.markdown",
  "working_dir": "$file_path"
}

Save the file as Rumdl.sublime-build.
Open a .md file and press Ctrl+B. If there are errors, they will appear at the bottom.

SublimeLinter Integration

If you want real-time red underlines as you type, you need to use the SublimeLinter framework.

Install SublimeLinter: Open the Command Palette (Ctrl+Shift+P), choose Package Control: Install Package, and select SublimeLinter.
Generic Linter Setup: Since there isn’t a SublimeLinter-rumdl package yet, you can use the SublimeLinter-shellcheck or similar “generic” command wrappers, but the most common way is to create a custom linter definition in your settings.
Open Preferences > Package Settings > SublimeLinter > Settings.
In the linters section of your User settings, add:

"linters": {
  "rumdl": {
    "executable": "rumdl",
    "args": ["check"],
    "selector": "text.html.markdown"
  }
}