Specifically, according to the company, “The majority of open-source software exclusively developed by Twitter is licensed under the liberal terms of the Apache License, Version 2.0. The documentation is generally available under the Creative Commons Attribution 3.0 Unported License. In the end, you are free to use, modify and distribute any documentation, source code or examples within our open source projects as long as you adhere to the licensing conditions present within the projects.” Twitter’s open-source software ware is kept on GitHub.
You’re welcome to use this code. Indeed, Aniszczyk strongly encourages others to use and build on it.
Twitter itself is famous, or infamous in some circles, for having been built on Ruby on Rails. Today though Aniszczyk said, Twitter has moved to Java and a list of open-source programs longer than your arm.