Incidents always follow the saying: "users find out first." In reality, there are many cases where internal metrics look fine but user experience is broken. The reverse is also true—metrics are red while users keep using the service without any problems. If an operator only looks at system internals, it's hard to handle both situations correctly. Today's topics—Synthetics Canary, RUM, X-Ray, and ServiceLens—are tools for setting up monitoring from the "user perspective" rather than from "inside the system."