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

94Health
Tool npm

Vite

Next-generation frontend build tool with an instant dev server, lightning-fast HMR, and optimized production builds.

82,823
MIT
Used by 324
91Health
Tool npm

prettier

An opinionated code formatter that enforces consistent style across every language your project speaks.

52,263
MIT
Used by 310
92Health
Library npm

postcss

A CSS transformation engine that parses styles into an AST, letting JS plugins lint, prefix, and rewrite CSS — the foundation beneath Autoprefixer, Tailwind, and 200+ other tools.

28,972
MIT
Used by 277
86Health
Framework npm

Express

The fast, unopinionated, minimalist web framework for Node.js

69,454
MIT
Used by 158
96Health
Framework npm

Next.js

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

142,310
MIT
Used by 154
75Health
Library Cargo

serde_json

The de facto standard JSON library for Rust, built on the Serde serialization framework

5,636
Apache 2.0
Used by 111
89Health
Library npm

sharp

High-performance Node.js image processing powered by libvips, built for fast resizing and format conversion.

32,677
Apache 2.0
Used by 109
56Health
Library npm

fs-extra

Drop-in replacement for Node's fs module adding copy, remove, mkdirs, and JSON helpers with native promise support.

9,589
MIT
Used by 84
90Health
Framework PyPI

FastAPI

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

102,333
MIT
Used by 76
60Health
Library npm

diff

A battle-tested JavaScript library for computing and applying text diffs at the character, word, line, sentence, CSS, or JSON level.

9,207
BSD 3
Used by 70
92Health
Library npm

undici

A fast, spec-compliant HTTP/1.1 client for Node.js, built from scratch with zero runtime dependencies

7,695
MIT
Used by 70
83Health
Library npm

Pino

A super fast, low-overhead JSON logger for Node.js applications.

18,194
MIT
Used by 67
90Health
Framework npm

Hono

A small, ultrafast web framework built on Web Standards that runs identically everywhere.

32,186
MIT
Used by 60
94Health
Framework npm

TanStack Router

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

15,081
MIT
Used by 56
60Health
Library npm

Winston

A battle-tested Node.js logging library with pluggable transports, custom formats, and multiple log levels.

24,520
MIT
Used by 50
93Health
Library PyPI

urllib3

A powerful, user-friendly HTTP client for Python with thread-safe connection pooling, TLS verification, and retry handling.

4,058
MIT
Used by 48
68Health
Library npm

proxy-agent

Maps HTTP, HTTPS, SOCKS, and PAC proxy protocols to the correct Node.js http.Agent implementation automatically.

1,161
MIT
Used by 47
90Health
Library npm

Prisma Client

Auto-generated, type-safe database client for Node.js and TypeScript.

47,610
Apache 2.0
Used by 46
85Health
Library PyPI

PyJWT

A Python implementation of RFC 7519 for encoding, decoding, and verifying JSON Web Tokens.

5,700
MIT
Used by 44
95Health
Library npm

Socket.IO

Bidirectional, low-latency, event-based realtime communication for Node.js and the browser.

63,200
MIT
Used by 39
92Health
SDK npm

@clickhouse/client

The official TypeScript client for connecting Node.js applications to ClickHouse over HTTP.

331
Apache 2.0
Used by 38
84Health
Library npm

body-parser

Node.js body-parsing middleware that turns raw HTTP request bodies into ready-to-use req.body objects.

5,499
MIT
Used by 36
83Health
Library npm

type-fest

A collection of essential, ready-made TypeScript utility types beyond the built-in standard library.

17,409
Other
Used by 32
55Health
Library npm

superjson

Serialize JavaScript to a superset of JSON that keeps Dates, Maps, Sets, BigInts, and more intact.

5,277
MIT
Used by 32

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