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

50Health
Tool npm

Peggy

Parser generator for JavaScript using parsing expression grammars (PEG)

1,179
MIT
Used by 5
52Health
SDK npm

@neondatabase/serverless

Neon's serverless PostgreSQL driver for JavaScript and TypeScript, built for edge and serverless runtimes using HTTP and WebSockets instead of raw TCP.

548
MIT
Used by 5
69Health
Library npm

yargs-parser

The mighty, standalone option parser powering yargs

519
Other
Used by 5
43Health
Library npm

error-stack-parser

Cross-browser JavaScript library that parses Error objects into structured stack frames with function names, file paths, and line/column numbers.

486
MIT
Used by 5
59Health
Library Cargo

tree-sitter-c-sharp

C# grammar for tree-sitter, based on the Roslyn language grammar

321
MIT
Used by 5
70Health
Library Cargo

x509-parser

A pure-Rust, zero-copy X.509 certificate parser (RFC 5280) built on the nom parser-combinator framework, with optional signature verification.

277
Other
Used by 5
65Health
Library PyPI

tinycss2

Low-level CSS Syntax Level 3 parser and generator for Python

190
BSD 3
Used by 5
80Health
Framework npm

graphql-yoga

A fully-featured, spec-compliant GraphQL server built on the WHATWG Fetch API, running anywhere from Node to Cloudflare Workers.

8,531
MIT
Used by 4
82Health
Library PyPI

lark

A modern parsing toolkit for Python supporting Earley, LALR(1), and CYK parsers with automatic tree construction.

5,983
MIT
Used by 4
78Health
Library Go

jsonparser

A fast, allocation-free JSON parser for Go that reads values by key path without unmarshaling into structs.

5,654
MIT
Used by 4
96Health
Library Composer

Device Detector

Universal PHP library for parsing user agents into browsers, OS, and device info

3,526
Other
Used by 4
41Health
Library npm

snarkdown

A dead-simple, dependency-free Markdown-to-HTML parser that weighs about 1kb gzipped.

2,401
MIT
Used by 4
39Health
Library npm

url-parse

Small, dependency-light URL parser that works identically in Node.js and the browser.

1,034
MIT
Used by 4
82Health
Library PyPI

MyST Parser

An extended CommonMark-compliant Markdown parser with first-class bridges to docutils and Sphinx.

889
MIT
Used by 4
88Health
Library PyPI

Griffe

Extract signatures and structure from entire Python programs for API docs and breaking-change detection.

691
Other
Used by 4
33Health
Library npm

url-pattern

A tiny, dependency-free library for matching and generating URL-like string patterns without regex.

587
MIT
Used by 4
74Health
Library Go

go-shellwords

A Go library that splits shell-style command-line strings into argument slices, honoring POSIX quoting, escaping, and substitution rules.

576
MIT
Used by 4
39Health
Library Cargo

roxmltree

Parse XML into a fast, read-only tree in Rust with zero unsafe code and no dependencies.

535
Apache 2.0
Used by 4
57Health
Library Cargo

tree-sitter-c

The official C grammar for the tree-sitter incremental parsing library

392
MIT
Used by 4
35Health
Library npm

@iarna/toml

A fast, spec-compliant TOML parser and stringifier for Node.js with a familiar JSON-style interface.

340
Other
Used by 4
39Health
Library npm

accept-language-parser

Parse HTTP Accept-Language headers and pick the best matching locale

165
MIT
Used by 4
35Health
Library npm

parse-diff

A fast, dependency-free unified diff parser that converts raw patch text into structured file, chunk, and line-change objects for JavaScript and TypeScript projects.

99
MIT
Used by 4
62Health
Framework npm

Backbone

A lightweight MV* framework that gives JavaScript-heavy applications structure with Models, Views, Collections, Routers, and Events.

28,101
MIT
Used by 3
49Health
Library Composer

Parsedown

Fast, single-class Markdown parser for PHP with no dependencies beyond mbstring.

15,060
MIT
Used by 3

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