The textbook outlines the basic principles of e-commerce in a simple and accessible form. The characteristics of the Internet are given, electronic payment systems are considered, the content and technologies of financial transactions in interactive mode are disclosed, much attention is paid to Internet commerce and mobile commerce. The book is equipped with test questions, tests and a dictionary of terms. For students and teachers of higher and secondary specialized educational institutions, as well as for practitioners in the business sector where the Internet is used (banks, insurance companies, exchanges, trade enterprises, etc.).