Twitter is built on open source software, from the back-end to the front-end. Twitter engineers use, contribute to and release a lot of open source software. We of the Twitter Open Source Program Office support a variety of open source organizations and are grateful to the open source community for their contributions, and want to maintain our healthy, reciprocal relationship.

via Open Source | Twitter Developers.

If you’re interested in the projects we have released, check out our official organization on GitHub.