Global, Reduce latency, health checks, no failover = Amazon CloudFront Global ,Reduce latency, health checks, failover, Route traffic = Amazon Route 53 option A has more weight.

A. I'm not an expert in this area, but I still want to express my opinion. After carefully reviewing the question and thinking about it for a long time, I actually don't know the reason. As I mentioned at the beginning, I'm not an expert in this field.

B: Caching solution. Not ideal for failover although it will work. Would have been a correct answer if A wasn't an option C: Transit gateway is for VPC connectivity not AWS API or Lambda D: Even if it was possible, there is a primary region dependency of ALB A: correct because R53 health checks can failover across regions Good explanation here: https://aws.amazon.com/blogs/compute/building-a-multi-region-serverless-application-with-amazon-api-gateway-and-aws-lambda/

we can set primary and secondry regions in cloud front for failover.

Application is serverless, it doesn't matter where it runs, so can be active-active setup and run wherever the request comes in. Route 53 with health checks will route to a healthy region. B, could work too, but CloudFront is for caching which does not seem to help with an API. The goal here is "failover capabilities", not caching/performance/latency etc.

In activ active failover config, route53 continuously monitors its endpoints and if one of them is unhealthy, it excludes the region/endpoint from its valid traffic route - Only Sensible option Cloudfront is a content delivery network - not used to route traffic Transit gateway for traffic routing - aws devs will hit us with a stick on hearing this option You cant use a load balancer for cross region load balancing - invalid

Global ,Reduce latency, health checks, failover, Route traffic = Amazon Route 53

"What the?" yeah I know right

"Stateless applications provide one service or function and use content delivery network (CDN), web, or print servers to process these short-term requests. https://docs.aws.amazon.com/architecture-diagrams/latest/multi-region-api-gateway-with-cloudfront/multi-region-api-gateway-with-cloudfront.html

A option does make sense.

By creating an Amazon CloudFront distribution with origins in each AWS Region where the application is deployed, you can leverage CloudFront's global edge network to route traffic to the closest available Region. CloudFront will automatically route the traffic based on the client's location and the health of the origins using CloudFront health checks. Option A (creating Amazon Route 53 health checks with an active-active failover configuration) is not suitable for this scenario as it is primarily used for failover between different endpoints within the same Region, rather than routing traffic to different Regions.

https://aws.amazon.com/blogs/compute/building-a-multi-region-serverless-application-with-amazon-api-gateway-and-aws-lambda/

https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover.html

I understand that you can use Route 53 to provide regional failover.

To route traffic to multiple AWS Regions and provide regional failover capabilities for a stateless web application running on AWS Lambda functions invoked by Amazon API Gateway, you can use Amazon Route 53 with an active-active failover configuration. By creating Amazon Route 53 health checks for each Region and configuring an active-active failover configuration, Route 53 can monitor the health of the endpoints in each Region and route traffic to healthy endpoints. In the event of a failure in one Region, Route 53 automatically routes traffic to the healthy endpoints in other Regions. This setup ensures high availability and failover capabilities for your web application across multiple AWS Regions.

I think it's A because the keyword is "route" traffic.

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