uv venv VS python -m venv

TL;DR

python -m venv (Standard & Universal)

python -m venv .venv
source .venv/bin/activate

Pros

• Built into Python (no extra tools)
• Works everywhere
• Well-understood and predictable
• Ideal for simple scripts and legacy workflows

Cons

• Uses whatever Python is installed
• Slow environment creation
• No dependency locking or Python version pinning

Best when

• You want maximum portability
• You’re not using uv for dependency management
• You’re working in constrained environments (CI images, minimal containers)

uv venv (Modern, Fast, Reproducible)

uv venv .venv
source .venv/bin/activate

Pros

• ⚡ Extremely fast (often instant)

• Can download and pin Python versions

• Automatically compatible with:

  • uv add
  • uv pip install
  • uv sync

• Works seamlessly with uv.lock

• Ideal for reproducible builds

Cons

• Requires installing uv
• Tighter coupling to uv ecosystem
• Less familiar to teams used to pure pip

Best when

• You already use uv add, uv sync, or uv pip install
• You care about reproducibility
• You want Python version isolation without pyenv
• You’re building containers or CI pipelines

Key Difference That Matters Most

Python version handling

python -m venv
# Uses: system Python

uv venv
# Can auto-download the exact Python version

Example:

uv venv --python 3.11

No pyenv. No system Python conflicts.

Typical uv Workflow (Recommended)

uv venv
source .venv/bin/activate
uv add requests
uv sync

This gives you:

• Locked dependencies
• Consistent Python version
• Fast installs
• Reproducible environments

Docker Note (Relevant to Your Previous Context)

In Dockerfiles:

• Prefer uv venv + uv sync
• Avoid activating venv (just use full path)
• Works well with private PyPI / Artifactory setups

Example:

RUN uv venv /opt/venv \
 && /opt/venv/bin/uv sync

Recommendation

• Already using uv? → Use uv venv
• Need universal compatibility? → python -m venv
• CI / Docker / reproducibility? → uv venv