The error rate of an application is the frequency at which errors occur in the application. It measure the proportion of failed requests or operations relative to the total number of requests or operations over a given period.
For example, if an e-commerce website experiences a 5% error rate during peak traffic hours, it means that 5 out of every 100 transactions are resulting in errors, potentially leading to lost sales and poor user experience.
You can monitor the error rate of your application and identify patterns, anomalies, and potential causes of errors. Typically leveraging modern observability tools such as OpenTelemetry enable you to measure error rates and more importantly give you deep insights in your application that can lead to the root-cause of errors.