Jenkins: the free self-hosted server that builds and ships your code

Jenkins is an MIT-licensed automation server you install on your own hardware. It runs your build, test and deploy jobs from a Jenkinsfile kept in the repository, so the pipeline is versioned alongside the code it ships. Build minutes are limited by your machine rather than by a billing plan.

How it works

A controller schedules work and one or more agents execute it, which is how a single Jenkins installs scales past what one machine can build. Jobs trigger from a webhook, a poll of the repository, a schedule or a manual click.

The pipeline itself lives in a Jenkinsfile: stages for build, test and deploy, written in declarative syntax and stored in git. That is the part that matters years later. The build history is in the repository, not in somebody's memory of a GUI configuration. Plugins connect the controller to source control, credentials, cloud targets and notification tools.

What you need

• Java, or the official jenkins/jenkins:lts image, which brings its own runtime.
• Port 8080 for the interface and port 50000 if you attach agents over TCP.
• A git remote. Jenkins builds code, it does not host it.
• Disk for workspaces, build artifacts and the JENKINS_HOME directory, which is also what you back up.
• Somewhere to keep credentials: Jenkins has its own store, and using it is better than putting secrets in the Jenkinsfile.

What it does well

• Pipelines as code, so a build definition can be reviewed, diffed and rolled back like anything else in the repository.
• Breadth of integrations. Whatever you already run, there is probably a plugin for it, including the awkward internal systems.
• Builds code from any git host: GitHub, GitLab, Gitea or a bare remote. It does not force you onto one platform.
• Agents let you put heavy jobs on a bigger machine without moving the controller.
• No per-minute billing, which matters for long test suites and nightly jobs.

Where it falls short

• You own the upgrades. Plugin compatibility is the usual cause of a broken instance, and a long-lived install accumulates plugins nobody remembers adding.
• The interface is dated, and the learning curve around agents and credentials is real.
• Backup discipline is on you. Losing JENKINS_HOME means losing every job configuration.
• For a small team with one repository, the setup cost is more than a bundled CI would be.

How to install Jenkins

Option 1, one-click install: Hostinger deploys Jenkins as a preconfigured Docker app on a managed server, so there is no command line and nothing to configure. It runs builds and deployments with full VPS control.

Option 2, install it yourself: docker run -d --name jenkins -p 8080:8080 -p 50000:50000 -v jenkins_home:/var/jenkins_home jenkins/jenkins:lts, then open port 8080 and paste the initial admin password from the container logs.

FAQ

Is Jenkins free? Yes. MIT licensed, no paid tier, no per-user billing. The cost is the server and your time.

Do I need to know Groovy? Not for a basic pipeline. Declarative syntax in a Jenkinsfile covers most build and deploy jobs, and the web interface can generate a starting pipeline you then edit.

Why do plugin upgrades break builds? Plugins depend on each other and on a core version. Pin versions, upgrade in a staging instance first, and keep the pipeline in git so a rebuild is possible.

How do I back it up? Copy JENKINS_HOME. That directory holds job configuration, credentials and build history; everything else can be recreated.

Can it replace a hosted CI service? For builds and deploys, yes. It receives webhooks and runs the same stages. What you give up is managed runners and someone else handling upgrades.

Does it need a separate git server? Yes. Jenkins is the build system, not the repository host.

Last checked: November 2026. Licence read from the repository, and the Docker image and ports checked against Docker Hub and the official image documentation.