Continuous Integration and Continuous Delivery (CI/CD) platforms automate the build, test, and deployment pipeline that code travels through from PR to production. Core capabilities include pipeline definition as code (YAML), ephemeral runners across OS and architecture, matrix builds, dependency caching, secret injection, parallel and sequential job orchestration, approval gates, deployment strategies (blue-green, canary, rolling), and integrated security scanning. The category spans SCM-bundled CI/CD (GitHub Actions, GitLab CI/CD) that dominates new adoption, standalone CI providers (CircleCI, Buildkite, Jenkins), and GitOps-focused continuous-deployment engines for Kubernetes (Argo CD, Flux).