When you're just getting started with New Relic, you get a solid foundation for observability right out of the gate. However, no solution has absolutely everything, and finding the perfect monitoring solution can be challenging. Many folks in IT need to add custom metrics, events, logs, or traces to their existing monitoring solutions. To accommodate these needs, New Relic offers Flex, an application-agnostic integration that allows users to instrument any metric they can find. Flex requires installing the infrastructure agent on a system and configuring YAML files in the integrations.d directory. The YAML file must have specific guidelines, such as having a certain format, indents, and permissions. Users can create custom Flex integrations by creating YAML files with their desired metrics and settings. Once configured, these integrations will send data to New Relic. While Flex provides a flexible way to collect custom data, users need to understand how to query and visualize this data using New Relic Query Language (NRQL) or other tools. With Flex, users can create custom dashboards and charts with their collected data, providing more detailed insights into their systems' performance.