# Installation

This page covers everything you need to get multimark installed and working on your system, from prerequisites through verification.


# Requirements

Multimark requires Python 3.9 or later and a C compiler available at install time. The CFFI build step compiles the vendored cmark-gfm C library into a shared object that Python loads at runtime.

On most systems, the necessary build tools are already present. If you are working in a minimal container or a fresh virtual machine, you may need to install a compiler toolchain first.

<span class="gd-details-chevron" aria-hidden="true"></span><img src="data:image/svg+xml;base64,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" class="gd-details-icon" />Platform-specific compiler setup


**macOS**: Install the Xcode command-line tools if you have not already.

``` bash
xcode-select --install
```

**Ubuntu / Debian**:

``` bash
sudo apt-get install build-essential python3-dev
```

**Windows**: Install the [Build Tools for Visual Studio](https://visualstudio.microsoft.com/visual-cpp-build-tools/). Select the "Desktop development with C++" workload during installation.


# Installing from PyPI

The recommended way to install multimark is with pip inside a virtual environment.

``` bash
python -m pip install multimark
```

This downloads the source distribution, compiles the C extension, and installs the package. The entire process typically takes a few seconds on modern hardware.


# Installing from Source

For development or to get the latest unreleased changes, clone the repository and install in editable mode.

``` bash
git clone https://github.com/posit-dev/multimark.git
cd multimark
python -m pip install -e ".[dev]"
```

Editable mode means changes to the Python source files take effect immediately without reinstalling. However, if you modify the C source or the CFFI build script, you need to rebuild.


# Verifying the Installation

After installing, confirm that the package loads correctly and reports the expected library version.


``` python
import multimark

multimark.cmark_version()
```


    '0.29.0.gfm.13'


If this prints a version string like `0.29.0.gfm.13`, the C library was compiled and linked successfully.


# Dependencies

Multimark has a single runtime dependency: [cffi](https://cffi.readthedocs.io/). The build process also requires `cffi` (for generating the bindings) and a C compiler. There are no other third-party dependencies at runtime, keeping the installation lightweight and conflict-free.