How do I do an editable install with pip or uv?

Run `pip install -e .` or `uv pip install -e .` from the project directory. The `-e` flag tells the installer to link the source code instead of copying it into `site-packages`.

When should I use an editable install?

Use an editable install during package development when you frequently modify source code and need changes to take effect immediately. They are not intended for production environments.

Do editable installs work with compiled C extensions?

No. Compiled extensions are not automatically rebuilt when you change their source. You still need to recompile those manually after modifying C extension code.

What Is an Editable Install?

Q: What is an editable install in Python?

An editable install (also called a development install) installs a Python package so that changes to the source code are immediately reflected in the environment without requiring reinstallation. It creates a live link between the source directory and the Python environment using a `.pth` file in `site-packages`.

Q: What is PEP 660 and how does it relate to editable installs?

PEP 660 standardized editable installs so any PEP 517-compliant build backend can support them. Before PEP 660, editable installs were only available through setuptools' `setup.py develop` command. Now backends like Hatchling and Flit can provide editable installs through a common interface.

by Tim Hopper · Markdown

Packaging

An editable install (also called a “development install”) installs a Python package so that changes to the source code are immediately reflected in the environment without requiring reinstallation. Both pip and uv support editable installs via the -e flag. They are for active development; do not use them in production environments.

How Editable Installs Work

Under the hood, an editable install places a .pth file in the Python environment’s site-packages directory instead of copying the package files there. That .pth file points Python’s import system to the development directory containing the source code. Your IDE can find and interact with the actual source files.

Compiled extensions are not automatically rebuilt when you change their source. Recompile them manually after modifying C extension code.

Caveats

Moving or renaming the source directory breaks the .pth pointer silently; reinstall with -e after any such move.
Data files and package resources may resolve to source-tree paths rather than installed paths. Verify the behavior with a real wheel install before publishing.

How PEP 660 Standardized Editable Installs

PEP 660 introduced a standard hook API that any PEP 517-compliant build backend can implement to support editable installs. Before PEP 660, editable installs were only available through setuptools’ setup.py develop command. The PEP decoupled this workflow from setuptools, allowing backends like Hatch and Flit to support editable installs through a common interface.

Learn More

What is PEP 660? covers the standard that decoupled editable installs from setuptools
What is a build backend? explains the systems that implement editable installs
PEP 660 — Editable installs for pyproject.toml based builds

Last updated on July 10, 2026

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