What Is Continuous Integration, Delivery, and Deployment?

Continuous integration, delivery, and deployment (CI/CD) have become popular strategies as Agile development methodologies and DevOps practices have proliferated. CI/CD brings fast-moving application life cycles that update functionality and can ensure production availability better than older practices in which cycles moved more slowly and often brought substantial changes in large batches.

CI/CD terminology is often used loosely, but the terms refer to the following:

Continuous integration (CI) is a strategy in which every code check-in to a primary source control system branch triggers a full build and possibly automated tests to ensure that the check-in does not break the build or application release criteria, such as functionality and security. CI reduces build break debugging difficulties that occur when builds are not performed until many check-ins have been made.

Continuous delivery (CD) is a strategy in which development teams produce new application versions that can be used in production in short (for example, 30-day) cycles. The frequent releases provide customers with regular feature updates and bug fixes.