How to Use `--exclude-newer` for Reproducible Python Environments

The --exclude-newer option instructs uv to ignore any package versions published after the specified date. This creates a time-locked resolution process that ensures consistency regardless of when you run the installation.

uv add -r requirements.txt --exclude-newer 2023-12-12

This is particularly useful when reproducing historical environments or working with deprecated projects

For example, if you clone a repository last updated in June 2023, use the flag to only install dependencies that would have been available at that time:

git clone https://github.com/example/ml-model
cd ml-model
uv add -r requirements.txt --exclude-newer 2023-06-15