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

95Health
Framework npm

React Router

A multi-strategy router for React, from a lightweight library to a full SSR framework.

56,590
MIT
Used by 167
96Health
Framework npm

Next.js

The React framework for production: file-based routing, server rendering, and Rust-powered builds.

142,803
MIT
Used by 154
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
62Health
Framework npm

Commander.js

The complete, battle-tested framework for building Node.js command-line interfaces.

28,412
MIT
Used by 94
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
54Health
Framework Go

Cobra

The commander library that powers Kubernetes, Hugo, and GitHub CLI's command-line interfaces.

44,650
Apache 2.0
Used by 62
94Health
Framework npm

TanStack Router

A fully type-safe React router with built-in data loading, caching, and URL search-param validation.

15,136
MIT
Used by 57
75Health
Framework npm

yargs

The modern, pirate-themed command-line argument parser and command framework for Node.js

11,504
MIT
Used by 42
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
92Health
Framework npm

Docusaurus

React-based static site generator for building fast, maintainable documentation websites.

66,349
MIT
Used by 36
90Health
Framework npm

tRPC Server

Build end-to-end typesafe APIs in TypeScript with no schemas, no code generation, and zero runtime bloat.

40,666
MIT
Used by 35
97Health
Framework npm

React Native

Build native iOS and Android apps from a single React codebase using the components and patterns you already know.

126,751
MIT
Used by 31
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
88Health
Framework npm

Expo

Open-source framework for building universal native apps with React that run on Android, iOS, and the web.

52,467
MIT
Used by 27
92Health
Framework npm

Lexical

An extensible, framework-agnostic text editor framework for building reliable, accessible rich-text experiences on the web.

23,901
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
77Health
Framework Go

Gin

A high-performance HTTP web framework for Go, built on a zero-allocation radix-tree router with an Express.js-style API.

89,268
MIT
Used by 22
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
93Health
Framework npm

preact

Fast, 3kB React-compatible Virtual DOM library with the same modern component API.

38,892
MIT
Used by 19
92Health
Framework PyPI

LangGraph

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

42,375
MIT
Used by 18
92Health
Framework Go

urfave/cli

A declarative, dependency-free Go package for building fast, friendly command-line tools.

24,260
MIT
Used by 17

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