Azure Stack is a hybrid cloud computing software solution developed by Microsoft based on the company's Azure cloud platform.
It is designed to help organizations deliver Azure services from their own data center.
It combines infrastructure-as-a-service (IaaS) and platform-as-a-service (PaaS) services in a software stack that spans on-premises datacenter environments as well as Microsoft's Azure cloud. Both Azure and Azure Stack share a standardized architecture, including the same portal, a unified application model and common DevOps tools.
In order to handle address hybrid cloud issues, such as inconsistency between cloud and on-premises environments, Microsoft Azure and Azure Stack shares its code, APIs and management portal.
Microsoft positions Azure Stack for those types of organizations that must contend with regulations or other constraints that require them to keep certain data private but want to tap into the benefits of a cloud-like platform.