Directory

Open Source Packages

Libraries, frameworks, tools, and SDKs used by the apps in this directory — scored the same way as the apps themselves.

5929 packages

All Packages

96Health
Framework PyPI

pytest

The Python testing framework that makes writing small tests easy and scales to complex functional test suites.

14,543
MIT
Used by 100
91Health
Tool PyPI

Uvicorn

A lightning-fast ASGI server for Python, built on uvloop and httptools.

10,993
BSD 3
Used by 83
91Health
Framework PyPI

FastAPI

A modern, high-performance Python web framework for building APIs with automatic validation, serialization, and interactive docs.

102,676
MIT
Used by 78
90Health
Tool PyPI

Ruff

An extremely fast Python linter and code formatter, written in Rust, built as a drop-in replacement for Flake8, Black, isort, and dozens of plugins.

49,811
MIT
Used by 46
95Health
Framework PyPI

aiohttp

Asynchronous HTTP client and server framework for Python's asyncio, covering both API calls and building web/WebSocket services.

16,561
Apache 2.0
Used by 40
95Health
Framework PyPI

Transformers

State-of-the-art pretrained models for text, vision, audio, and multimodal inference and training.

166,736
Apache 2.0
Used by 38
88Health
Tool PyPI

Gunicorn

A fast, lightweight pre-fork WSGI and ASGI HTTP server for running Python web apps in production on UNIX.

10,686
MIT
Used by 33
83Health
Tool PyPI

mypy

Optional static type checker that catches Python bugs before you run your code

20,651
MIT
Used by 30
81Health
Framework PyPI

Flask

A lightweight WSGI web framework for Python that scales from a single file to complex applications.

74,802
BSD 3
Used by 28
89Health
Tool PyPI

Alembic

Database migrations tool for SQLAlchemy with autogenerate and transactional DDL

4,413
MIT
Used by 27
89Health
Framework PyPI

Typer

Typer is a Python library for building CLI applications, using type hints to generate arguments, options, validation, help text, and shell completion automatically.

20,033
MIT
Used by 26
87Health
Framework PyPI

Django

The high-level Python web framework that turns database models into secure, working web applications in record time.

91,218
BSD 3
Used by 24
92Health
Framework PyPI

LangChain

The most widely adopted Python framework for building LLM-powered agents and applications

147,170
MIT
Used by 21
94Health
Framework PyPI

Starlette

A lightweight ASGI framework/toolkit for building async web services and apps in Python

12,639
BSD 3
Used by 21
92Health
Framework PyPI

LangGraph

A low-level orchestration framework for building stateful, multi-actor LLM agents as graphs

42,375
MIT
Used by 18
91Health
Framework PyPI

django-rest-framework

The most widely-used toolkit for building Web APIs on top of Django, with serializers, viewsets, and a built-in browsable API.

30,191
BSD 3
Used by 15
88Health
Framework PyPI

FastMCP

The fast, Pythonic framework for building Model Context Protocol servers, clients, and apps

27,913
Apache 2.0
Used by 14
91Health
Framework PyPI

Pydantic AI

A type-safe Python agent framework built by the Pydantic team

20,217
MIT
Used by 14
86Health
Tool npm

js-beautify

Reformats and re-indents JavaScript, HTML, and CSS into clean, readable code

8,999
MIT
Used by 11
51Health
Tool PyPI

MkDocs

A fast, simple static site generator for building project documentation from Markdown with a single YAML config file.

22,470
Other
Used by 10
74Health
Tool Composer

Laravel IDE Helper

Generate accurate PHPDocs for Laravel facades, models, and macros to power IDE autocompletion.

14,967
MIT
Used by 9
89Health
Framework PyPI

OpenAI Agents SDK

OpenAI's provider-agnostic Python framework for building multi-agent LLM workflows with tools, guardrails, and tracing.

29,733
MIT
Used by 8
92Health
Tool PyPI

isort

Automatically sorts and organizes Python import statements

6,953
MIT
Used by 8
69Health
Tool PyPI

flake8

The CLI linter that wraps PyFlakes, pycodestyle, and McCabe complexity checks into a single Python style and error checker.

3,823
MIT
Used by 8

Join founders buildingwith open source

Opinionated takes, migration guides, cost-saving tips, and insights from the open source ecosystem.

Subscribe on Substack
Join 750+ subscribers