- AWS www.sitereliabilityengineering.co AWS FIS is for running fault injection experiments on AWS to improve an application’s performance, observability, and resiliency. Fault injection experiments are used in chaos engineering for stressing an application in testing or production environments by creating disruptive events, observing how the system responds, and implementing improvements. FIS provides controls and guardrails to run experiments, such as automatically rolling back or stopping the experiment if specific conditions are met.