Working with UV

UV is a fast Python package manager and virtual environment tool built in Rust. It’s a drop-in replacement for pip, venv, and virtualenv, and it’s well suited to lightweight, reproducible Python environments — a good fit for use with Zasper.

This guide shows how to create and configure a Python project using UV and register it as a Jupyter kernel for use in Zasper.

Step 1: Create a New Project

Start by initializing a new Python project with UV:

uv init exampleUV
cd exampleUV
uv run main.py   # creates a .venv directory automatically

The .venv directory is your virtual environment — an isolated space where you can install dependencies without affecting your global Python installation.

Step 2: Activate the Virtual Environment

To use the environment in your terminal session:

source .venv/bin/activate

This activates the environment so that any Python or pip commands you run use the local .venv.

Step 3: Install Packages

Install the ipykernel package, which allows the environment to be used as a kernel in Jupyter-based tools like Zasper:

uv pip install ipykernel

You can also install any additional libraries your project needs at this stage.

If you open this folder in Zasper now, it already lists the environment: a project’s own .venv with ipykernel in it appears first in the Launcher as Python 3.x (.venv), with no registration needed. Zasper’s Set up a Python kernel button does steps 1 to 3 for you when a project has no kernel yet — see Installing Jupyter Kernels.

Step 4: Register the Kernel (Optional)

Register the environment only if you want to use it from other projects too, or from Jupyter itself:

uv run python -m ipykernel install --user --name=exampleUV

This creates a new kernel spec named exampleUV. It will now appear as an option in the Zasper kernel selector wherever Zasper is opened.

You’re All Set

Launch Zasper in the exampleUV folder, choose Python 3.x (.venv) — or the exampleUV kernel if you registered it — and run code in your new environment.