New Relic Flex is an application-agnostic tool for collecting metric data from various services without a suitable agent, allowing for an agentless approach to gather telemetry data from external sources exposed only through an API layer. Australia Post partnered with New Relic to minimize instability in their systems caused by erratic weather and manage demand during these periods. The company set up a simple configuration file using the New Relic Flex binary or infrastructure agent, which targets current weather and records city as a custom attribute. The configuration was then expanded to include hourly weather, precipitation, rain, and showers data, and finally sent to New Relic for analysis and decision-making purposes, providing valuable insights into external factors impacting their applications.