Q4 of 38 · CI/CD & DevOps
What's the difference between continuous integration and continuous deployment?
Short answer
Short answer: CI integrates code frequently, automatically building and testing every change. Continuous *delivery* takes integrated code and prepares it for release, awaiting manual promotion. Continuous *deployment* removes the manual step — every passing build goes to production automatically.
Detail
Three distinct concepts, often muddled.
Continuous Integration (CI) — every commit/push triggers automated build + test. The goal is to catch integration bugs early, before they pile up into a painful merge. Hallmarks: small frequent commits, fast pipeline (< 10 min), trunk-based development.
Continuous Delivery (CD-delivery) — every CI-passing build is automatically deployed to a staging or pre-production environment. From there, a human (or release process) promotes to production. The build is deployable any time, but the call to deploy is manual. Useful when you need compliance sign-off, scheduled releases, or coordination with marketing.
Continuous Deployment (CD-deployment) — every CI-passing build deploys to production automatically. No human gate. Requires high test confidence, monitoring, and the ability to roll back fast. Common at companies like Netflix, Amazon (deploys per second).
Why teams confuse them: "CD" is overloaded. Some companies say "we have CI/CD" and mean "build and deploy on push to main" — that's continuous deployment. Others mean "build automatically and click-to-deploy" — that's continuous delivery.
Practical question to clarify: "When code is merged to main, does it go to production automatically, or does a human click a button?" Automatic = continuous deployment. Click = continuous delivery.
Risk profile differs significantly. Continuous deployment puts much higher pressure on tests, monitoring, and rollback. Continuous delivery offers a safety net at the cost of release latency.