---
title: "Installation"
description: "Install the justcatit package and the .NET runtime it needs; update and remove it."
url: "https://docs.justcat.it/reference/python-module/installation/"
---
# Installation


## Prerequisites

**A 64-bit Python, 3.8 or later.** The package depends on [pythonnet](https://pypi.org/project/pythonnet/), a compiled extension that is released for a range of Python versions — pip picks the pythonnet release that fits your Python; a Python newer than the latest pythonnet release cannot install the module until pythonnet catches up.

**An installed .NET runtime, version 10 or later.** The package does not bring its own runtime; pythonnet finds the one installed on the machine (through `DOTNET_ROOT` or `dotnet` on `PATH`) and uses the highest version it finds. Without one, the first function call fails with `RuntimeError: Failed to create a .NET runtime (coreclr)`. On Windows:

```
winget install Microsoft.DotNet.Runtime.10
```

or download the **.NET Runtime** (x64) from <https://dotnet.microsoft.com/download/dotnet/10.0>. The .NET SDK works too but is not needed.

**Windows x64** is the only supported platform — see [Platforms](https://docs.justcat.it/reference/python-module/introduction/#platforms "Platforms"). On Linux and macOS, use the PowerShell module or CAT CLI instead.

Some data source providers need additional software installed on the machine. The requirement belongs to the provider, not to the module — each provider page states what it needs, and the [Providers overview](https://docs.justcat.it/reference/data-sources/providers/overview/ "Providers overview") marks which providers need a driver.

## Install

```
pip install justcatit
```

(`py -m pip install justcatit` on Windows when `pip` is not on `PATH`.) The package is large — it carries the CAT engine — so the first install takes a moment. Pin the version in automated processes: `pip install justcatit==3.0.0`.

## Verify the installation

```python
from justcatit import cat
print(cat.get_instance())
```

`get_instance` needs neither a token nor a key; it prints the instance (versions, platform, whether a key is set) and proves the .NET runtime was found.

## Update

```
pip install --upgrade justcatit
```

## Uninstall

```
pip uninstall justcatit
```

Uninstalling removes the package only. Project files, test definitions and results stay where they are; the license key and instance identity stay in `%APPDATA%\CAT\` for the other CAT tools.

## Related

- [Introduction](https://docs.justcat.it/reference/python-module/introduction/ "Introduction") — import, session model, sign-in.
- [Get started with the Python module](https://docs.justcat.it/get-started/python-module/ "Get started with the Python module") — the tutorial.