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

90Health
Library npm

Tailwind CSS

A utility-first CSS framework for rapidly building custom user interfaces without leaving your markup.

97,558
MIT
Used by 340
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
88Health
Library npm

Autoprefixer

Parses your CSS and automatically adds vendor prefixes using real-world browser usage data from Can I Use.

22,229
MIT
Used by 198
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
34Health
Library npm

tailwindcss-animate

Tailwind CSS plugin for enter and exit animations using utility classes

3,018
MIT
Used by 100
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
83Health
Library npm

Pino

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

18,194
MIT
Used by 67
90Health
Tool npm

Stylelint

An extensible CSS linter that catches errors and enforces consistent styling conventions.

11,519
MIT
Used by 58
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
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
91Health
Library npm

BullMQ

Fast, reliable Redis-based message queue and background job processing for Node.js and TypeScript.

9,396
MIT
Used by 41
63Health
Tool npm

postcss-loader

Runs PostCSS plugins on your CSS as part of a webpack build pipeline.

2,842
MIT
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
92Health
Framework Composer

PHPUnit

The de facto standard, programmer-oriented unit testing framework for PHP.

20,055
BSD 3
Used by 34
65Health
Library npm

postcss-import

A PostCSS plugin that inlines @import rules, merging split CSS files into one stylesheet before other plugins run.

1,410
MIT
Used by 33
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
87Health
Library npm

fast-xml-parser

Pure-JS XML parser, builder, and validator with no C/C++ bindings and no callbacks

3,139
MIT
Used by 32
93Health
Library Composer

Guzzle

An extensible PHP HTTP client for sending requests and integrating with web services

23,455
MIT
Used by 31
45Health
Library npm

zod-to-json-schema

Converts Zod validation schemas into standard JSON Schema, ready for OpenAPI, OpenAI, and JSON Schema draft 7 consumers.

1,252
Other
Used by 30

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