Pixi is basically uv but for the conda ecosystem in the sense that it has all the goodness (fast and reliable dependency solver, smart caching, using hardlinks for environment installs to speed things up and save space) and makes the whole environment/dependency management for conda project so much faster and more robust. For dependencies from PyPI, pixi uses the uv crate under the hood, so it doesn't waste effort on that front and works just as well.
I think many python project will be fine with just using uv but at least for my use case, pixi turned out to be just what I needed, because my software also needs to run on older macOS versions, Intel and Arm Macs, and packages like OpenCV or PyTorch are just not officially built for those anymore, but in the conda ecosystem, there are countless brave souls who build this stuff for macOS 11+ so I can just use that and it's such a relief.
Uv is getting most of the attention right now and I can totally understand why, but if python is your main thing and you want to keep up with what's the best the ecosystem can offer right now, you should at least give pixi a try and evaluate the pros and cons yourself. It's really worth it imo.
Builds still suck though.
Pixi shines in those niches where Conda was the only option. It seems ROS is one of them.
I have been using Pixi with emscripten-forge to create Python WASM distributions. It’s another niche with a lack of tooling. Pixi is the only tool that streamlined my build process.
Keep up with the good work!
As far as I can tell, pixi brings the benefits of these types of dependencies, with native support for multiple languages (python and c++ being the big ones).
ROS uses debian packages today (inside a convoluted wrapper), imo it would be much better if it went all in on pixi instead.