Application migration is the process of moving a software application from one computing environment to another. You might, for instance, migrate an application from one data center to another, from an on-premises server to a cloud provider's environment, or from the public cloud to a private cloud environment.

Various factors determine the migration pattern, including business function, objectives, business cycle, criticality and priority, application architecture and effort required. For example, a custom, off-the-shelf application may be more suitable for Rehost (rather than Replatform or Refactor).

Migration Tools are simply software that manages or automates the migration of components in a changing system (e.g. migrating an application to a new operating system or platform). This may facilitate the movement of a formerly on-premise service to the cloud, or support virtualization, or some other change.