The Service Quality Index (SQI) quantifies the quality of service provided by comparing the expected service against the perceived service delivered. It is often calculated through surveys that assess customer satisfaction across various service dimensions such as responsiveness, reliability, and assurance. In the web3 context, SQI can help gauge user experience in decentralized applications (dApps) and blockchain services by providing insights into customer expectations versus actual experience. Organizations use SQI to identify gaps in service delivery and to enhance their service offerings based on customer feedback.