What is the difference between CI, continuous delivery and continuous deployment?

Model answer

The three terms describe how far automation goes after a developer commits code.

Continuous integration (CI): developers merge small changes into the main branch often, and every change triggers an automated build and test run. The goal is to find integration problems early.
Continuous delivery: every change that passes the pipeline is built into a releasable artifact and can be deployed at any time, but a human presses the button for production.
Continuous deployment: the last manual step is removed. Every change that passes all automated checks goes to production automatically.

CI is the foundation for both. Continuous deployment needs strong automated tests, monitoring and a fast rollback path, because nobody reviews each release by hand.

Key points

CI: frequent merges with an automated build and tests on every change
Continuous delivery: always releasable, production deploy is a manual decision
Continuous deployment: every passing change ships automatically
Deployment automation needs tests, monitoring and fast rollback

Likely follow-ups

Which stages would you put in a CI pipeline and in what order?
When would you choose continuous delivery over continuous deployment?

Common mistakes

Using continuous delivery and continuous deployment as synonyms
Calling it CI when branches live for weeks before merging