been using uv on a flask container and honestly the diff in build times is just boringly huge. not even the speed tho, it's how predictable things get. no stupid “why did pip install this version” moments. you write a pyproject.toml, freeze with uv lock, done.

>In docker you can just raw COPY pyproject.toml uv.lock* . then run uv sync --frozen --no-install-project. this skips your own app so your install layer stays cacheable. real ones know how painful it is to rebuild entire layers just cuz one package changed.

>UV_PROJECT_ENVIRONMENT=/home/python/.local bypasses venv. which means base images can be pre-warmed or shared across builds. saves infra cost silently. just flip UV_COMPILE_BYTECODE=1 and get .pyc at build.

> It kills off mutable environments. forces you to respect reproducibility. if your build is broken, it's your lockfile's fault now. accountability becomes visible