Is there a difference between classic venv and uv's venv?

Python Help
1

As title. I’m used to create classic venvs, but I’m curious if uv’s venv offer some improvements.

2

My understanding is that the underlying venv is the same. Using uv makes creation that much simpler though.

3 
python -m venv py_venv
uv venv uv_venv
du -sh *_venv
diff -rq *_venv

12M	py_venv
80K	uv_venv
Files py_venv/bin/activate and uv_venv/bin/activate differ
Only in uv_venv/bin: activate.bat
Files py_venv/bin/activate.csh and uv_venv/bin/activate.csh differ
Files py_venv/bin/activate.fish and uv_venv/bin/activate.fish differ
Only in uv_venv/bin: activate.nu
Only in uv_venv/bin: activate.ps1
Only in py_venv/bin: Activate.ps1
Only in uv_venv/bin: activate_this.py
Only in uv_venv/bin: deactivate.bat
Only in py_venv/bin: pip
Only in py_venv/bin: pip3
Only in py_venv/bin: pip3.13
Only in uv_venv/bin: pydoc.bat
Files py_venv/bin/python and uv_venv/bin/python differ
Files py_venv/bin/python3 and uv_venv/bin/python3 differ
Files py_venv/bin/python3.13 and uv_venv/bin/python3.13 differ
Only in uv_venv: CACHEDIR.TAG
Files py_venv/.gitignore and uv_venv/.gitignore differ
Only in py_venv: include
Only in py_venv/lib/python3.13/site-packages: pip
Only in py_venv/lib/python3.13/site-packages: pip-24.2.dist-info
Only in uv_venv/lib/python3.13/site-packages: _virtualenv.pth
Only in uv_venv/lib/python3.13/site-packages: _virtualenv.py
Only in py_venv/lib64/python3.13/site-packages: pip
Only in py_venv/lib64/python3.13/site-packages: pip-24.2.dist-info
Only in uv_venv/lib64/python3.13/site-packages: _virtualenv.pth
Only in uv_venv/lib64/python3.13/site-packages: _virtualenv.py
Files py_venv/pyvenv.cfg and uv_venv/pyvenv.cfg differ
3 Likes
4

Hmmm… Does the default in one produce copies and in the other symlinks?

5

It’s site-packages that makes all the diference. venv bundles pip, while uv doesn’t need to.

󰅂 du -sh ??_venv/lib/python3.13/site-packages/*
12M	py_venv/lib/python3.13/site-packages/pip
104K	py_venv/lib/python3.13/site-packages/pip-24.2.dist-info
4.0K	uv_venv/lib/python3.13/site-packages/_virtualenv.pth
8.0K	uv_venv/lib/python3.13/site-packages/_virtualenv.py
1 Like
6

You could try to compare with python -m venv --without-pip py_venv. Maybe also try the --symlink option.

7

Ty for the diff. The fact that puzzle me of is that activate and deactivate scripts are different. I’m not a bash/cmd expert, so I can’t understand if there are radical changes or not.

8

Looks like uv venv adapted its activate scripts from virtualenv, not python -m venv.