Azure Front Door enables Azure owners to configure the global routing for their web traffic by allowing them to setup and optimize for best performance as well as to configure high availability through instant global fail-over.
Azure Front Door allows Azure administrators to transform their global, multi-regional consumer and enterprise solutions into high-performance solutions.
Azure Front Door works at Layer 7 of the OSI stack via the HTTP/HTTPS layer using the anycast protocol with split TCP and Microsoft’s global network backbone to better ensure global connectivity.
Based on your application setup and the configuration for your routing method solution, your client requests are directed to the fastest and most available application back-end.
Azure Front Door provides a range of traffic-routing methods and backend health monitoring options to suit different application needs and automatic fail-over models.
Similar to Traffic Manager, Front Door is resilient to failures, including the failure of an entire Azure region.
There are some differences between the two services and a couple of similarities.
Author iamashishsharma at https://iamashishsharma.com/ recently posted on their blog the post titled Difference between Azure Front Door Service and Traffic Manager – I highly recommend you read it; it is a very compact overview expressly outlining a couple of the similarities between the services and then the divergence of the two and what each offers.