Jenkins is an open-source automation server that orchestrates continuous integration and continuous delivery (CI/CD) workflows through pipelines defined as code. Originally forked from Hudson in 2011, Jenkins powers CI/CD pipelines across millions of projects worldwide by executing builds, running tests, and deploying applications through a distributed architecture of controllers (formerly masters) and agents (formerly slaves). Its plugin ecosystem with 2000+ plugins, combined with Pipeline-as-Code via Jenkinsfiles stored in source control, enables teams to automate every stage from commit to production while maintaining full version control and auditability of their delivery processes.