Open source products used in Twitter
Twitter uses many open source products and also contributes most of the code to open source. Here is the list of open source products used by Twitter. This list does not include the projects sponsored by twitter. https://github.com/twitter has the list of projects sponsored by twitter.
Programming language: Twitter uses C++, Java, Scala and Ruby.
Cassandra is a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's Column Family-based data model. http://cassandra.apache.org/
Redis is an advanced key-value store. http://redis.io/
Memcache is high-performance, distributed memory object caching system. http://memcached.org/
Lucene is a most popular and widely used java based search engine library. http://lucene.apache.org/java/
Scribe is a server for aggregating log data that's streamed in real time from clients.https://github.com/facebook/scribe
Hadoop is a framework for running applications on large clusters built of commodity hardware. http://hadoop.apache.org/
Hive is a data warehouse system for Hadoop that facilitates easy data summarization, ad-hoc queries, and the analysis of large datasets stored in Hadoop compatible file systems. http://hive.apache.org/
Avro is a data serialization system. It is a sub project of Apache Hadoop. http://hadoop.apache.org/avro
Pig is a high-level data-flow language and execution framework for parallel computation. http://pig.apache.org/
Thrift is a software framework for scalable cross-language services development. It combines a software stack with a code generation engine to build services that work efficiently and seamlessly between programming languages. http://incubator.apache.org/thrift/
ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. http://zookeeper.apache.org/
Netty provides an asynchronous event-driven network application framework and tools. It is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. http://www.jboss.org/netty