Our Drupal 8 websites are true applications, often very complex ones. More and more workload is delegated to external systems, usually microservices, that are used for many different tasks. Architectures are always more distributed and fragmented. To trace the lifecycle of a single request that originates in a client, passes through all Drupal subsystems, reaches external (micro)services and comes back, it will become mandatory to track down problems and to optimize for performances. This is often time consuming and without the right tools may become very difficult. A simple unstructured log stream isn't enough anymore, we need to find a way to observe the details of what is going on. Observability is all about this and is based on structured logs, metrics and traces. In this talk we will see how to implement these techniques in Drupal, which tools and which modules to use to trace and log all requests that reach our website and how to expose and display useful metrics. We will integrate Drupal with OpenTelemetry, Monolog and Grafana to collect, scrape, store and visualize telemetry data.