---
id: napari-plugin-engine
version: "0.2.1"
license: MIT
license_treatment: permissive
maintenance: abandoned
---

# napari-plugin-engine — napari plugin engine, fork of pluggy

License: permissive · Maintenance: abandoned · Downloads: 180.7K/mo

## What it is and what it does

napari-plugin-engine is a fork of pluggy, adapted by the napari team to provide plugin discovery and hook execution. It allows applications to register and call plugins using either naming conventions or entry points, with features like lazy discovery, hook reordering, and enhanced metadata retrieval. The package includes type annotations and pytest fixtures for testing.

This is the first-generation napari plugin engine and is now deprecated. The napari project has moved to npe2 as the recommended plugin system for all new development. Existing plugins are encouraged to migrate. The package remains available for legacy compatibility but receives no active maintenance.

Use it for:

- Loading and executing plugins in legacy napari installations that have not yet migrated to npe2
- Testing plugin systems that use hook-based architecture with pytest fixtures
- Understanding the evolution of napari's plugin architecture before the npe2 transition
- Maintaining older napari-based applications that depend on the first-generation plugin engine

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

A plugin discovery and hook-calling system for napari, enabling applications to load and execute plugins registered via naming convention or entry points.

No. The package is officially deprecated and abandoned; the napari team explicitly recommends npe2 for all new plugins and existing plugins to migrate. Install only if you are maintaining legacy code that cannot yet move to npe2. For new development, use npe2 instead.

## Install

pip install napari-plugin-engine
uv add napari-plugin-engine
poetry add napari-plugin-engine

## Installing napari-plugin-engine

Before you install: Low install friction with a single runtime dependency (importlib-metadata). However, the package is abandoned—the repository is archived and officially deprecated in favor of npe2, with no active maintenance.

License in practice: MIT license permits free use, modification, and distribution with minimal restrictions, making it legally straightforward to adopt.

Quickstart:

pip install napari-plugin-engine

from napari_plugin_engine import HookimplementationMarker

hookimpl = HookimplementationMarker('napari')

Requires Python 3.6 or later; package is deprecated and no longer maintained.

Verify before relying:

- Whether existing napari installations still depend on this package or have migrated to npe2
- Compatibility with Python versions beyond 3.10 given the abandoned status
- Whether the lazy plugin discovery feature remains performant in production deployments

## Package facts

- License: MIT (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: abandoned
- Downloads: 180.7K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

plugin discovery and registration, hook system for extensibility, napari plugin loader, plugin engine framework, entry point plugin management, lazy plugin loading, deprecated, legacy-plugin-system

[View on SkillFed](https://skillfed.io/packages/napari-plugin-engine) · [View on PyPI](https://pypi.org/project/napari-plugin-engine/)