developer-experience

Make Contributing Effortless

The single biggest factor in whether someone contributes to a project is how fast they can get a working development environment. If clone-to-passing-tests takes more than 60 seconds, every additional minute costs potential contributors. FastAPI, Pydantic, and httpx all converge on the same pattern: one prerequisite (uv), one command (uv sync --group dev), and every common task wrapped in a Makefile target. Invest in developer experience early -- every minute spent here pays back tenfold in contributor time saved.

One-Command Dev Setup

Target clone-to-running-tests in under 60 seconds. The modern standard uses uv with a committed lock file.

git clone https://github.com/org/my-package
cd my-package
uv sync --group dev     # Creates venv, installs package + all dev deps
uv run pytest           # Tests pass on first try

What makes this possible:

• Commit uv.lock to the repo for deterministic installs across machines
• Use PEP 735 dependency groups ([dependency-groups] in pyproject.toml) with a dev group
• Require no environment variables or config files to get started
• Rely on uv to install the correct Python version automatically

Step	Legacy (2020)	Modern (2026)
Install Python	pyenv install 3.x	uv handles it
Create virtualenv	python -m venv .venv	uv sync creates it
Activate	source .venv/bin/activate	Not needed (uv run)
Install deps	pip install -r requirements-dev.txt	uv sync --group dev
Install package	pip install -e .	Included in uv sync
Run tests	pytest	uv run pytest
Total commands	5-6	2 (clone + sync)

Task Automation with Makefile

Wrap every common operation in a Makefile target. Contributors type make test instead of remembering uv run pytest --cov --cov-report=term-missing -x -v. Use make help as the default target to make commands discoverable.

Required targets: