Jenkins

Jenkins is a free, open-source automation server, best known as a continuous integration and continuous delivery (CI/CD) tool. It watches source repositories, runs builds and tests when code changes, and can carry a release all the way to production. It is written in Java and is one of the longest-running CI projects: it began as Hudson, created by Kohsuke Kawaguchi, and was renamed Jenkins by its community in 2011.

Unlike hosted CI services, Jenkins is software you install and operate yourself. That gives full control over where builds run and what they can reach, at the cost of maintaining the server, its agents and its plugins. The project is released under the MIT licence and is a graduated project of the Continuous Delivery Foundation.

Key features

• Pipeline as code. A Jenkinsfile in the repository defines stages such as build, test and deploy, in declarative or scripted syntax, so pipeline changes are versioned and reviewed like code.
• Multibranch builds. Pipelines run automatically for each branch and pull request.
• Distributed builds. A controller hands work to agents on other machines, so builds and tests can run in parallel across Linux, Windows and other platforms.
• Durable pipelines. Pipelines can survive controller restarts, pause for human approval and run steps in parallel.
• Plugins. More than 2,300 community plugins connect Jenkins to Git hosts, build tools, Docker, Kubernetes, issue trackers and chat services.
• Two release lines. Weekly releases bring new features quickly; Long-Term Support releases pick a new baseline every 12 weeks and receive fixes every four weeks.

Who it is for

Jenkins suits teams that need CI/CD on their own infrastructure: organisations with code that cannot leave their network, builds that need special hardware, or long-established pipelines built around its plugins. It is also common in enterprises with a platform team that can own the server. Small teams with no one to maintain it may find a hosted service simpler.

Pricing at a glance

• Software: free and open source under the MIT licence, with no paid edition from the project.
• Running costs: you pay for the servers, cloud instances or Kubernetes capacity that host the controller and build agents, plus the time to operate them.

Licence terms as checked on 10 October 2026; see the project site for current details.

Things to consider

• Security is your responsibility: the controller, agents and every plugin need regular updates, and plugins vary in how actively they are maintained.
• Large plugin sets can conflict after upgrades; test updates on a copy before applying them to production.
• Packages for macOS and some other systems are maintained by third parties, and the download page warns they may lack the latest security fixes.
• Choose LTS for predictable updates, or weekly if you need new features quickly.

Getting started

1. Pick an installation method from the installation guide; the Docker image is the quickest way to try it.
2. Unlock Jenkins with the initial admin password and install the suggested plugins.
3. Create a Pipeline or Multibranch Pipeline job pointing at your repository.
4. Add a Jenkinsfile with build and test stages and push it.
5. Add agents and credentials, and enable notifications such as Slack.