Blue-Green Deployment
Running two identical production environments and switching traffic between them atomically, for a release with zero downtime.
Blue-green deployment keeps two full, identical production environments — one (blue) live and serving traffic, one (green) idle. A new release deploys to the idle environment, gets tested against real infrastructure with no user traffic, and once verified, traffic is switched to it atomically — instantly and completely, rather than gradually like a canary — with the old environment kept warm as an instant rollback target.