Glossary · Definition
CI/CD
CI/CD is the automation that turns 'I pushed code' into 'it's tested, built, and deployed'. CI (continuous integration) runs tests + builds on every commit; CD (continuous delivery / deployment) ships the result to staging or production automatically.
Definition
CI/CD is the automation that turns 'I pushed code' into 'it's tested, built, and deployed'. CI (continuous integration) runs tests + builds on every commit; CD (continuous delivery / deployment) ships the result to staging or production automatically.
What it means
A typical pipeline triggers on git push: it lints, type-checks, runs unit + integration tests, builds the container or static bundle, scans for vulnerabilities, and (on the main branch) deploys. GitHub Actions, GitLab CI, CircleCI, and Buildkite are common runners; Vercel, Netlify, Cloudflare Pages bundle CI/CD with hosting. 'Continuous Delivery' means every passing build is *deployable*; 'Continuous Deployment' means every passing build IS deployed (no manual gate). Most teams start with delivery and add deployment as confidence in the test suite grows.
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Why it matters
Without CI/CD, deploys are big infrequent events that break things. With it, deploys are small frequent non-events. Real wins: catch bugs before they merge, ship hotfixes in minutes not hours, and free engineering time from manual deploy choreography. Real costs: pipeline maintenance, flaky tests eroding trust in green builds, secret management, and the temptation to deploy at the speed of CI rather than the speed of customer safety.
Frequently asked questions
What's a flaky test?
A test that sometimes passes and sometimes fails on the same code — usually because of timing, randomness, or shared state. Flaky tests train the team to ignore failures, defeating CI's whole point. Quarantine or fix them aggressively.
How long should CI take?
Under 10 minutes for the path 'PR opened → green check'. Past 15 minutes, developers context-switch away and the feedback loop dies. Parallelism, test partitioning, and caching dependencies are the standard fixes.
What's a feature flag?
A runtime switch that lets you ship code disabled. Combined with continuous deployment, you ship code in tiny increments and turn features on for a small percentage of users to limit blast radius.
Related terms
- DefinitionDockerDocker packages an app plus its OS-level dependencies into a portable container — a lightweight, isolated process that runs the same way on every host. The image is the recipe; the container is a running instance.
- DefinitionKubernetesKubernetes (k8s) orchestrates many containers across many machines. You declare the desired state — 'run 3 replicas of this image, expose this port, restart on crash' — and the control plane keeps reality matching it.