Jenkins is an open-source automation server that helps to automate the building, testing, and deployment of applications. It provides a framework for Continuous Integration (CI) and Continuous Delivery (CD), which helps teams to quickly and easily deploy code changes to production. Jenkins also provides a wide range of plugins that can be used to extend its functionality and integrate it with other tools in the software development lifecycle. With Jenkins, teams can automate repetitive tasks, reduce manual errors, and improve software quality and release speed.