https://learn.microsoft.com/en-us/azure/frontdoor/front-door-faq#what-is-the-difference-between- azure-front-door-and-azure-application-gateway- While both Front Door and Application Gateway are layer 7 (HTTP/HTTPS) load balancers, the primary difference is that Front Door is a non-regional service whereas Application Gateway is a regional service. While Front Door can load balance between your different scale units/clusters/stamp units across regions, Application Gateway allows you to load balance between your VMs/containers etc. that is within the scale unit.