What Is a CI/CD Pipeline?

A CI/CD pipeline is the automated assembly line that turns a code change into a tested, deployable, and deployed application.

Every modern software team relies on some form of pipeline, even if it is just a handful of scripts. A CI/CD pipeline formalizes the steps between "a developer pushed code" and "that code is running in production" so they happen the same way every time, without manual hand-offs. This lesson defines the pipeline, explains the CI and CD halves, and shows why automation here matters more than almost anywhere else in software delivery.

CI and CD: two halves of one path

CI stands for continuous integration: developers merge their work into a shared branch frequently, and each merge automatically triggers a build and a test run. CD stands for either continuous delivery (every validated change is *ready* to ship at the click of a button) or continuous deployment (every validated change ships automatically with no human gate). The pipeline is the machinery that connects these ideas into a single, repeatable flow.

What actually happens in a pipeline

When you push a commit, a CI server detects the change and runs a sequence of steps in order. A typical first pass checks out the code, installs dependencies, compiles or bundles it, runs automated tests, and produces an artifact. If any step fails, the pipeline stops and reports the failure so nothing broken proceeds toward production. The pipeline is defined as code (often a YAML file like .github/workflows/ci.yml) so the process is version-controlled alongside the application.

Why teams automate this

Consistency: the same steps run every time, eliminating "works on my machine" surprises.
Speed: feedback on a broken change arrives in minutes instead of after a manual review.
Safety: code cannot reach production without passing the gates the team defined.
Scale: dozens of engineers can integrate work daily without stepping on each other.

Where pipelines run

Pipeline steps execute on machines called runners or agents. These can be hosted by your CI provider (GitHub-hosted runners, for example), self-managed on your own infrastructure, or provided by a managed platform. The pipeline definition tells the provider what to run; the runner is the actual computer that does the work.

Key takeaways

A CI/CD pipeline is an automated path from commit to production.
CI integrates and tests changes continuously; CD delivers or deploys them.
Pipelines are defined as code and run on machines called runners.