API Observability is a key component to properly execute APIOps Cycles and ensure your building something of value for your API users. If you’re not familiar with APIOps Cycles, take a look at this guide which provides an agile framework to quickly build APIs that are business-oriented and serve customer needs. API Observability itself is an evolution of traditional monitoring and born out of control systems theory.
Traditional monitoring focuses on tracking known unknowns. This means you already know what to measure like Request Per Second or Errors Per Second. While the metric value may be unknown beforehand, you already know what to measure or probe such as a counter to track requests into buckets. This makes it possible to report on the health of a system (like Red, Yellow, Green), but is a bad tool for troubleshooting engineering or business issues which usually require asking arbitrary questions.