ContinuousDelivery

Continuous Delivery is a software development practice in which code changes are automatically built, tested, and prepared for a release to production. The goal is to make software releasable at any time, with a manual decision to deploy, or with automated deployment in a related approach called continuous deployment. Continuous delivery extends continuous integration by ensuring that build artifacts pass a broad set of automated tests and quality checks and can be deployed to production-like environments on demand.

A typical delivery pipeline includes version control, automated build, automated testing (unit, integration, and end-to-end), static analysis and security checks, artifact packaging, and deployment to staging environments. Infrastructure as code and deployment automation enable reproducible environments. In staging, additional automated and manual validation may occur before the release is approved for production. In continuous deployment, production deployments occur automatically whenever a change passes all tests. Practices such as automated rollback, feature flags, and continuous monitoring help manage risk.

Benefits of continuous delivery include faster feedback cycles, smaller and safer releases, improved release reliability, and closer alignment with DevOps and agile methodologies. Challenges involve achieving comprehensive test coverage, managing data migrations, maintaining environment parity, and meeting governance or compliance requirements in regulated contexts.

The concept gained prominence in the 2000s and was popularized by Jez Humble and David Farley in their work on Continuous Delivery. It is closely related to continuous integration, continuous deployment, and broader DevOps practices, and is supported by tooling such as Jenkins, GitLab CI, CircleCI, Azure Pipelines, and AWS CodePipeline.