How is CI different from CD?

Continuous Integration (CI) and Continuous Delivery (CD) are two terms that are often used interchangeably by developers. However, although CI and CD are similar in their implementation of automation, they differ in practice.

CI is an ongoing method which culminates in testing of code before it is integrated with the main branch; while CD continues after this integration step, whereby the previously tested code is automatically pushed through to staging and then on-demand pushed to a production server.

If a DevOps engineer enables continuous deployment, the final stage of deployment onto production servers is also automated. Although this may prove convenient for developers who can receive feedback as soon as possible, customers may find frequent software updates disruptive due to downtime caused during such procedures.