Path based

You can create a listener with rules to forward requests based on the URL path. This is known as path-based routing. If you are running microservices, you can route traffic to multiple back-end services using path-based routing. For example, you can route general requests to one target group and request to render images to another target group.

This path-based routing allows you to route requests to, for example, /api to one set of servers (also known as target groups) and /mobile to another set. Segmenting your traffic in this way gives you the ability to control the processing environment for each category of requests. Perhaps /api requests are best processed on Compute Optimized instances, while /mobile requests are best handled by Memory Optimized instances.

Host based

You can create Application Load Balancer rules that route incoming traffic based on the domain name specified in the Host header. Requests to api.example.com can be sent to one target group, requests to mobile.example.com to another, and all others (by way of a default rule) can be sent to a third. You can also create rules that combine host-based routing and path-based routing. This would allow you to route requests to api.example.com/production and api.example.com/sandbox to distinct target groups.