napari is a fast, interactive, multi-dimensional image viewer for Python. It’s designed for browsing, annotating, and analyzing large multi-dimensional images. It’s built on top of Qt5 (for the GUI), VisPy (for performant GPU-based rendering), and the scientific Python stack (numpy, scipy).



napari can be installed on most macOS, Linux, and Windows systems with Python 3.7 and 3.8 using pip:

pip install 'napari[all]'

napari needs a library called Qt to run its user interface (UI). In Python, there are two alternative libraries to run this, called PyQt5 and PySide2. By default, we don’t choose for you, and simply running pip install napari will not install either. You might already have one of them installed in your environment, thanks to other scientific packages such as Spyder or matplotlib. If neither is available, running napari will result in an error message asking you to install one of them.

To install napari with a specific UI framework, you can use

pip install 'napari[pyqt5]'
# or
pip install 'napari[pyside2]'
# or
pip install 'napari[all]'

This last option (pip install napari[all]) will choose a framework for you — currently PyQt5, but this could change in the future.

Tutorials & getting started

If you are just getting started with napari, we suggest you check out the tutorials at The documentation presented here is more technical and focuses on understanding how napari works.

Developer introduction

Information on specific functions, classes, and methods is available in the API Reference.