Mystery shopping is a method used by marketing research companies and organizations that wish to measure quality of sales and service, job performance, regulatory compliance, or to gather specific information about a market or competitors, including products and services.
Wikipedia
Traditionally mystery shopping has been associated with customer experience on physical stores or other locations of business. Now take the same approach to measure digital experiences. Digital mystery shopping is not just one visit to your shop and writing a report about it but holistic test framework to see how consumers are experiencing your digital service or ecommerce with various needs, devices and intentions.