The original open-source CI/CD automation server
Jenkins is the most widely used CI/CD server with a massive plugin ecosystem and flexible pipeline-as-code via Jenkinsfile. While newer tools like GitHub Actions gain ground, Jenkins remains dominant in enterprises due to its flexibility, self-hosted nature, and extensive customization. Jenkins Pipeline (Declarative and Scripted) enables complex build, test, and deployment workflows. Its 1,800+ plugins integrate with virtually every tool in the DevOps landscape.