What is a canary cookie?

A canary cookie is a type of web cookie used primarily for monitoring and detecting changes in user behavior or system performance. It serves as a "canary in a coal mine," alerting developers to potential issues or anomalies in web applications. When a specific condition is met, such as a change in user engagement or performance metrics, the canary cookie can trigger alerts for further investigation. This practice helps ensure that applications run smoothly and user experiences remain optimal.