Pixi for Robotics

Pixi is not only for robotics, but it's a great fit for it!

Pixi is a fast, reproducible package manager built on the conda ecosystem, and a natural fit for robotics development.

If you're familiar with the traditional ROS setup, here's the mental model:

• apt installs Debian packages from the Ubuntu distribution. The official ROS apt repository (packages.ros.org) is an additional channel built on top of it.
• Pixi installs conda packages from the conda-forge distribution, RoboStack is an additional conda channel built on top of it in exactly the same way: it repackages the ROS ecosystem as conda packages, resolving all native dependencies against conda-forge.

The structure is identical: a base distribution (Ubuntu / conda-forge) with a ROS channel layered on top (packages.ros.org / robostack-<distro>). The key difference is that conda packages are cross-platform and not tied to a specific OS, so the same pixi.toml can work on Linux, macOS, and Windows without a system-wide install.

Pixi and RoboStack are currently a Tier 3 platform in the ROS ecosystem, which means they are community-supported but not officially supported by Open Robotics. Open Robotics has communicated that Pixi will be part of their strategy to expand accessibility and ease of use. So with your help, we can grow the community and make it a first-class way to use ROS on any platform.

Quick Start

Get ROS 2 Humble running in no time:

pixi init my_ros_ws -c https://prefix.dev/robostack-humble -c https://prefix.dev/conda-forge
cd my_ros_ws
pixi add ros-humble-desktop
pixi run rviz2

ROS 2 is installed, isolated to this workspace, and reproducible on any machine with Pixi. A pixi.toml file is created with the dependencies and channels, and a pixi.lock file is generated to pin exact versions. Use pixi run or pixi shell to activate the environment and run ROS commands.

Why Pixi for Robotics

• No system-wide ROS installation

  All dependencies live in the workspace. New team members clone the repo and run pixi install. No more additional setup instructions, no version incompatibilities.

• Reproducible environments

  Pixi generates a lockfile (pixi.lock) that pins every dependency, including transitive ones. The same environment is guaranteed on your laptop, CI, and the robot itself.

• Works on Linux, macOS, and Windows

  RoboStack supports ROS packages for Linux, macOS and Windows. A single pixi.toml can declare support for all three platforms simultaneously.

• Built-in task runner

  Define your colcon build, launch files, and simulation commands as named tasks in pixi.toml, no Makefiles or shell scripts needed.

• Mix ROS and non-ROS dependencies

  Python libraries, OpenCV, PyTorch, compilers, GUI's and ROS packages all managed together.

• Package and distribute your own nodes

  Build your ROS packages as conda packages with the pixi-build-ros backend and publish them to a private channel.

How Pixi Compares

• apt is Debian-only and install packages globally, making it hard to run different ROS versions side by side or reproduce the exact same setup across machines.
• pip can't install ROS or non-Python system libraries at all.
• Docker gives you isolation and improves cross-platform support but adds overhead, complicates GPU and hardware access, and requires a separate toolchain.
• Pixi gives you the package isolation and reproducibility of Docker with the native performance and hardware access of a local install, on any platform.

Guides

RoboStack

RoboStack is the community that maintains the conda ROS packages Pixi depends on.

Finding packages

Browse available packages for each distribution on prefix.dev. Package names follow the pattern ros-<distro>-<package-name>, mirroring the apt naming convention. There are more packages on the prefix.dev channels so some might normally come from apt or pip instead, but they are all available in a single place for Pixi:

What to do if a package is missing

Not all ROS packages are available in RoboStack yet. If you need a package that is not in the channel:

• Check the RoboStack GitHub to see if there is an open issue or PR for it.
• Contribute to RoboStack to add it. See the RoboStack contributing guide.
• Package it yourself with Pixi using the pixi-build-ros backend and publish it to your own conda channel.

rosdep is not supported

rosdep calls apt or pip under the hood, which bypasses Pixi's environment. Use pixi add to add any missing dependencies instead.

pixi-ros

pixi-ros can be used to quickstart a ROS workspace. This project can initialize a workspace with the correct RoboStack channels and ROS dependencies, and generate pixi.toml files for ROS packages.

# Install the pixi-ros CLI tool globally
pixi global install pixi-ros
# Move to your existing ros workspace that contains the src folder
cd ros_ws
# Initialize the workspace
pixi ros init

This will initialize a pixi.toml based on the package.xml files in your src folder, and add the necessary RoboStack channel automatically.

Common Patterns

Multi-machine workspace

Share the exact same environment across development machines and the robot:

[workspace]
channels = ["https://prefix.dev/robostack-humble", "https://prefix.dev/conda-forge"]
platforms = ["linux-64", "osx-arm64"]

[dependencies]
ros-humble-desktop = "*"
colcon-common-extensions = "*"

Using Pixi with colcon

Assuming you have a workspace with a src folder containing your ROS packages, you can define the following manifest in the root of your workspace:

[workspace]
channels = ["https://prefix.dev/robostack-humble", "https://prefix.dev/conda-forge"]
platforms = ["linux-64", "osx-arm64", "win-64"]

[dependencies]
ros-humble-desktop = "*"
colcon-common-extensions = "*"

[tasks]
# A simple colcon build task
build = "colcon build --symlink-install"

[activation]
# After you use colcon to build your workspace, Pixi has to source the setup script to make the new packages available in the environment
scripts = ["install/setup.sh"]

The activation scripts will be run on pixi run or pixi shell, so after the first build, you can run your ROS nodes with pixi run without needing to source the setup script manually.

Automate your workflow with tasks

[tasks]
# A simple alias for running the turtlesim simulator
sim   = "ros2 run turtlesim turtlesim_node"
# Use inputs to cache the build task and only rerun it when files in src change
build = {cmd = "colcon build --symlink-install", inputs = ["src"]}
# A task that depends on the build task, so it will only run after a successful build
run   = {cmd = "ros2 run my_package my_node", depends-on = ["build"]}

pixi run sim
pixi run run

run runs both the build and run commands in sequence, but if you run it again without changing any files in src, it will skip the build step since the inputs haven't changed.

Mixing ROS with Python ML libraries

# Tell pixi that it can install CUDA dependencies in this workspace
pixi workspace system-requirements add cuda 12

# (re)install ROS and your ML dependencies together
pixi add ros-humble-desktop pytorch torchvision opencv

Community & Support

• Pixi Discord: get help and share your projects
• conda-forge: the conda distribution Pixi is built on, with thousands of packages
• RoboStack: the conda channel that packages ROS for Pixi
• Pixi GitHub: report issues, contribute, and follow development