Observability is a crucial part of every DevOps journey and fundamental for proper operations at every scale. We will give an introduction to it, with particular focus on what we need to measure when we build developer platforms and how can we leverage metrics, logs and traces to run them efficiently and securely. We will talk about DORA metrics, SRE principles, foundational DevOps practices to help you build a secure and accessible Internal Developer Platform, with particular focus on security and self-service.