Twitter, Inc.

A set of primitives for parallel computation in Torch

A Scala API for Cascading

Pelikan is Twitter's unified cache backend

A fault tolerant, protocol-agnostic RPC system

Fast, testable, Scala services built on Twitter-Server and Finagle

A Thrift parser/generator

Memcache on SSD

Wonderful reusable code from Twitter

Abstract Algebra for Scala

Heron is a realtime, distributed, fault-tolerant stream processing engine from Twitter

A tool for benchmarking RPC services

Twitter's collection of LZO and Protocol Buffer-related Hadoop, Pig, Hive, and HBase code.

Twitter-Server defines a template from which services at Twitter are built

Security related headers all in one gem

Storehaus is a library that makes it easy to work with asynchronous key value stores

hRaven collects run time data and statistics from MapReduce jobs in an easily queryable format

Cloudhopper Commons

Twitter common libraries for python and the JVM

Find potential bugs in your services with Diffy

Twitter Emoji for Everyone

Lessons in the Fundamentals of Scala

GraphJet is a real-time graph processing library.

SPDY for iOS and OS X

Cache Commons

typeahead.js is a fast and fully-featured autocomplete library

A stats collector & reporter for Scala servers

Ruby implementation of the ICU (International Components for Unicode) that uses the Common Locale Data Repository to format dates, plurals, and more.

Scala extensions for the Kryo serialization library

Twitter's fork of Apache BookKeeper (will push changes upstream eventually)