# Blue-Green Deployment | | In software engineering, blue–green deployment is a method of installing changes to a web, app, or database server by swapping alternating production and staging servers. | |-|-| | | wikipedia:: [Blue–green deployment](https://en.wikipedia.org/wiki/Blue%E2%80%93green_deployment) | - prod and staging environments behind a load balancer. Then update one until it is verified as good. Then switch the load balancer to it and upgrade the other one.