Open Source

Introduction

Facebook has been developed from the ground up using open source software. Developers building with Platform scale their own applications using many of the same infrastructure technologies that power Facebook.

Want to learn more? Check out Engineering at Facebook.

Platform

Our Platform engineering team has released and maintains open source SDKs for Android, iOS, JavaScript and PHP.

Developer tools

codemod assists with large-scale codebase refactors that can be partially automated but still require human oversight and occasional intervention.

is a JavaScript library for creating customizable animations using DOM and CSS manipulation.

Online Schema Change for MySQL lets you alter large database tables without taking your cluster offline.

Phabricator is a collection of web applications which make it easier to write, review, and share source code. It is currently available as an early release and is used by hundreds of Facebook engineers every day.

PHPEmbed makes embedding PHP truly simple for all of our developers (and indeed the world) we developed this PHPEmbed library which is just a more accessible and simplified API built on top of the PHP SAPI.

phpsh provides an interactive shell for PHP that features readline history, tab completion, and quick access to documentation. It is ironically written mostly in Python.

Three20 is an Objective-C library for iPhone developers which provides many UI elements and data helpers that were used in older versions of our iPhone applications.

XHP is a PHP extension which augments the syntax of the language such that XML document fragments become valid expressions.

XHProf is a function-level hierarchical profiler for PHP with a simple HTML-based navigational interface.

Infrastructure

Apache Cassandra is a distributed storage system for managing structured data that is designed to scale to a very large size across many commodity servers, with no single point of failure.

Apache Hive is data warehouse infrastructure built on top of Hadoop that provides tools to enable easy data summarization, adhoc querying and analysis of large datasets.

FlashCache is a general purpose writeback block cache for Linux. It was developed as a loadable Linux kernel module, using the Device Mapper and sits below the filesystem.

HipHop for PHP transforms PHP source code into highly optimized C++. HipHop offers large performance gains and was developed over the past two years.

Open Compute Project an open hardware project aims to accelerate data center and server innovation while increasing computing efficiency through collaboration on relevant best practices and technical specifications.

Scribe is a scalable service for aggregating log data streamed in real time from a large number of servers.

Thrift provides a framework for scalable cross-language services development in C++, Java, Python, PHP, and Ruby.

Tornado is a relatively simple, non-blocking web server framework written in Python. It is designed to handle thousands of simultaneous connections, making it ideal for real-time Web services.

Our engineers contribute to

Apache Hadoop provides reliable, scalable, distributed computing infrastructure which we use for data analysis.

Apache HBase is a distributed, versioned, column-oriented data store built on top of the Hadoop Distributed Filesystem.

Cfengine is a rule-based configuration system that is used to automate the config and maintenance of servers. Facebook uses Cfengine to maintain host configs and to automate many janitorial operations on our production tiers.

jemalloc is a memory allocator which is fast, consistant, and supports heap profiling. Facebook engineers added heap profiling and made many optimizations. Learn more.

memcached is a distributed memory object caching system. Memcached was not originally developed at Facebook, but we have become the largest user of the technology.

MySQL is the backbone of our database infrastructure. You can find our patches on Launchpad and learn more about how we use it on the MySQL@Facebook page.

PHP is an incredibly popular scripting language which makes up the majority of our code-base. Its simple syntax lets us move fast and iterate on products.

Varnish serves billions of requests every day to Facebook users around the world. Whenever you load photos and profile pictures of your friends, there's a very good chance that Varnish is involved.

Mirror

We host a public mirror for projects such as Apache, Centos, CPAN, Fedora, GNU, Mozilla, MySQL, and much more...

Licensing

Our Documentation and Code Licensing page has more information about open source licensing for the projects we contribute to and release.