A customer KPI is a quantifiable metric that businesses can use to monitor and evaluate how customers respond to their business. Without any doubt, customers are the most important part of any business. Customers and clients will buy the goods and services that you sell. Therefore, you must measure exactly how your business interacts or engages them. The effectiveness of customer delivery is evaluated using these KPIs. You must be able to measure customer KPIs for your business to determine if you are losing or gaining customers. They will also let you know if your customers are displeased with anything and how to best attend to them and keep them happy.