Explore Facebook’s Top 20 Open‑Source Projects Ranked by GitHub Stars

1. ReactJS – JavaScript library for building user interfaces

https://github.com/facebook/react – Star 71.9k

React (also called React.js or ReactJS) is an open‑source JavaScript library released by Facebook for rendering data as HTML views and building user interfaces. It uses a component model with a one‑way data flow, enabling efficient updates and clean separation of UI components.

2. HHVM – Virtual machine for executing PHP code

https://github.com/facebook/hhvm – Star 14,884

HipHop VM (HHVM) is Facebook’s JIT‑based virtual machine for PHP, offering fast code generation and just‑in‑time compilation. Facebook claims HHVM runs PHP code up to 60% faster while reducing memory usage by 90% compared to the standard interpreter.

3. Flow – Static type checker for JavaScript

https://github.com/facebook/flow – Star 13,893

Flow is a static type‑checking tool for JavaScript developed by Facebook using OCaml. It helps developers find type errors in JavaScript code before runtime.

4. osquery – SQL‑driven operating‑system monitoring tool

https://github.com/facebook/osquery – Star 9,993

osquery provides a SQL interface for querying operating‑system information on macOS and Linux. It enables low‑level OS monitoring and analysis by allowing users to write SQL queries to inspect system data.

5. RocksDB – Embedded key‑value storage system

https://github.com/facebook/rocksdb – Star 8,780

RocksDB is an embeddable, persistent key‑value store derived from LevelDB, designed for high performance on flash storage and suitable for use as a C/S database.

6. Stetho – Android debugging bridge

https://github.com/facebook/stetho – Star 8,634

Stetho is an open‑source Android debugging tool from Facebook that integrates Chrome Developer Tools, allowing inspection of network, database, and WebKit components, as well as providing a powerful command‑line interface via dumpapp.

7. Phabricator – Visual code‑review platform

https://github.com/phacility/phabricator – Star 8,708

Phabricator is a web‑based code‑review tool that lets engineers discuss and approve code changes interactively, enforcing review policies before code is merged.

8. Yoga – Cross‑platform layout engine

https://github.com/facebook/yoga – Star 8,516

Yoga is a cross‑platform implementation of the CSS Flexbox layout algorithm, offering familiar APIs for designers and developers to build consistent UI layouts across platforms.

9. Infer – Static analysis tool for mobile apps

https://github.com/facebook/infer – Star 7,476

Infer is a static program analysis tool used by Facebook to detect potential bugs in Android, iOS, Messenger, and Instagram codebases before release.

10. Nuclide – Atom‑based development suite

https://github.com/facebook/nuclide – Star 7,171

Nuclide is a set of development tools built on Atom, providing features such as autocomplete, JavaScript type checking with Flow, and built‑in support for React and React Native.

11. Presto – Distributed SQL query engine for big data

https://github.com/prestodb/presto – Star 6,613

Presto is a high‑performance, distributed SQL engine designed by Facebook for interactive analytics on petabyte‑scale data sets, delivering query speeds up to ten times faster than Hive.

12. GraphQL – API query language

https://github.com/facebook/graphql – Star 6,293

GraphQL is a query language for APIs that lets clients request exactly the data they need, enabling efficient data fetching and reducing over‑fetching.

13. Caffe2 – Deep‑learning framework

https://github.com/caffe2/caffe2 – Star 6,068

Caffe2 is a fast, modular deep‑learning framework derived from Caffe, supporting deployment on iOS, Android, and Raspberry Pi for training and inference.

14. Mcrouter – Memcached protocol router

https://github.com/facebook/mcrouter – Star 2,038

Mcrouter is a high‑performance router for memcached, capable of handling up to 5 billion requests per second in large‑scale cache deployments.

15. Huxley – Web UI testing tool

https://github.com/facebookarchive/huxley – Star 4,077

Huxley, written in Python, captures screenshots of web pages and reports visual differences, helping developers verify UI changes.

16. ReDex – Android bytecode optimizer

https://github.com/facebook/redex – Star 3,760

ReDex provides a framework for reading, analyzing, and optimizing Android .dex files, applying a set of transformations to improve runtime performance.

17. Surround 360 – 360° video capture system

https://github.com/facebook/Surround360 – Star 1,706

Surround 360 is an open‑source hardware and software solution for capturing high‑quality 360° video, offering end‑to‑end pipelines for multi‑camera stitching.

18. libPhenom – High‑performance C concurrency framework

https://github.com/facebook/libphenom – Star 1,506

libPhenom is a C library that provides event‑driven, multi‑threaded concurrency primitives, memory management, and common data structures, including JSON handling.

19. ELF – Lightweight game research platform

https://github.com/facebookresearch/ELF – Star 1,096

ELF is a flexible platform for AI research in games, supporting board games, Atari, and custom real‑time strategy environments, runnable on GPUs and offering both C/C++ and Python interfaces.

20. LinkBench – Database benchmark tool

https://github.com/facebookarchive/linkbench – Star 332

LinkBench simulates Facebook’s MySQL workload to benchmark and tune database systems, reproducing mixed data models and social‑graph request patterns.