# Jenkins
Confidence: high
Last verified: 2026-05-22
Generation: human_only


## TL;DR

Jenkins (Kohsuke Kawaguchi, 2011, forked from Hudson) is the most established open-source CI/CD automation server. Jenkins Pipeline (Jenkinsfile, Groovy DSL) defines build/deploy as code. Over 1800 plugins. Jenkins is Java-based, highly extensible but complex to maintain.

## Core Explanation

Pipeline: `pipeline { agent any; stages { stage('Build') { steps { sh 'make' } } } }`. Declarative vs. Scripted pipeline. Jenkinsfile stored in repository (Pipeline as Code). Plugins: Git, Docker, Slack, Blue Ocean (modern UI). Master-Agent architecture for distributed builds. Modern alternatives: GitHub Actions (simpler, cloud-native), GitLab CI.

## Further Reading

- [Jenkins Documentation](https://www.jenkins.io/doc/)