Essential Python Packages#

Each entry below links to a dedicated page with purpose, install command, code examples, outputs, and common pitfalls.

HTTP & Networking#

Package	Install	Purpose
requests	`pip install requests`	Sync HTTP client — the classic choice
httpx	`pip install httpx`	Modern sync + async HTTP client

Package	Install	Purpose
numpy	`pip install numpy`	N-dimensional arrays and vectorized math
pandas	`pip install pandas`	DataFrames for tabular data
matplotlib	`pip install matplotlib`	2-D plotting and figure generation
scipy	`pip install scipy`	Scientific algorithms (stats, optimize, signal)
pillow	`pip install pillow`	Image reading, transformation, and saving

Package	Install	Purpose
asyncio	(stdlib — no install)	Built-in async/await event loop

Package	Install	Purpose
pathlib	(stdlib — no install)	Object-oriented filesystem path handling

Package	Install	Purpose
click	`pip install click`	Decorator-based CLI builder
rich	`pip install rich`	Terminal formatting, tables, progress bars

Package	Install	Purpose
pydantic	`pip install pydantic`	Runtime type validation with Python type hints

Package	Install	Purpose
sqlalchemy	`pip install sqlalchemy`	ORM + SQL toolkit for Python

Package	Install	Purpose
flask	`pip install flask`	Lightweight WSGI micro-framework
django	`pip install django`	Full-featured batteries-included framework
fastapi	`pip install fastapi`	Fast ASGI API framework with auto-docs

Package	Install	Purpose
loguru	`pip install loguru`	Structured logging with zero configuration

Package	Install	Purpose
jupyter	`pip install jupyterlab`	Interactive notebooks for data exploration

Package	Install	Purpose
pytest	`pip install pytest`	Test discovery, fixtures, and parametrize

Package	Install	Purpose
mypy	`pip install mypy`	Static type checker

Package	Install	Purpose
ruff	`pip install ruff`	Fast all-in-one linter and formatter (replaces black + flake8 + isort)
black	`pip install black`	Opinionated code formatter

Package	Install	Purpose
uv	`curl -LsSf https://astral.sh/uv/install.sh \| sh`	Blazing-fast installer and project manager
poetry	`pip install poetry`	`pyproject.toml`-based dependency management and publishing

New project, greenfield? → Use uv for environment + deps, ruff for linting, pytest for tests, pydantic for validation.
Building a REST API? → fastapi + pydantic + sqlalchemy.
Quick internal tool? → flask (small) or django (if you need admin/auth out of the box).
Data analysis script? → pandas + matplotlib; add scipy for statistics.
HTTP calls? → requests for sync, httpx for async or when you want HTTP/2.
Logging? → loguru for new projects; it replaces logging with zero boilerplate.
Data exploration? → jupyter + pandas + matplotlib — run cells interactively.
Async concurrency? → asyncio (stdlib) + httpx for async HTTP or fastapi for async APIs.
File paths? → pathlib (stdlib) — never use os.path.join() again.

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