The blue/green deployment technique enables you to release applications by shifting traffic between two identical environments that are running different versions of the application. Blue/green deployments can mitigate common risks associated with deploying software, such as downtime and rollback capability. This whitepaper provides an overview of the blue/green deployment methodology and describes techniques customers can implement using Amazon Web Services (AWS) services and tools. It also addresses considerations around the data tier, which is an important component of most applications.