The aim of the article. The aim of the article is to study the global trends of e-commerce as a complex form of economic relations and to provide its diagnostics based on key performance indicators, as well as to substantiate the strategic guidelines for e-commerce development in Ukraine and the world. Analyses results. E-commerce has become an integral part of the economy since the birth of the Internet and the active digitalization of modern life and business processes. The COVID-19 pandemic and related quarantine restrictions have led to the active growth of e-commerce in the world, as well as the development of forms and methods of its realization. During 2019-2020, the number of sellers and buyers who enjoy benefits from online transactions has significantly increased. Business processes in e-commerce are characterized by an increased level of innovation, but also increased risk and uncertainty. The Internet access is spreading rapidly around the world, with the number of e-commerce entities increasing. In 2020, more than two billion people bought goods or services online, and global e-retail sales exceeded $ 4.28 trillion. The expected figure for 2021 is $ 4.5 trillion. More than 40% of the world's retail online sales are made through Amazon network, and its subsidiary Amazon Web Service is the world leader in online services. In terms of GMV, Amazon (USA) ranks third after China. Taobao and Tmall platforms, managed by Alibaba Group, are leaders in online commerce in Asia and the world. In addition to the main key performance indicators of digital technologies, such as bounce rate, page time and conversion rate, the following indicators were used for diagnostics: time spent per page; the share of unseen content; site pages scroll rate. Another important trend in e-commerce is the spread of mobile commerce, i.e. the use of mobile devices to search for goods and services and make online transactions. Mobile phones account for the bulk of online traffic in all industries, and in 2020, 64% of Internet traffic came from smart phones. The e-commerce effectiveness indicator is the failure rate – the share of transactions not finalized by making an order and payment, i.e. the percentage of "abandoned baskets". The average industry-wide failure rate has not changed since 2019 and was 47% in 2020. Choosing a reliable platform and e-commerce payment system is an important aspect of doing business online as it reduces bounce rates. The time spent on the page is an indicator of the site visitors' satisfaction with the available content or their interest in the information. On average, a user spends a little less than a minute (54 seconds) on each page during their visit. The “Unseen content share” is the ratio of information that is not viewed to the total amount of information on the site. In 2020, it was discovered that 45% of all content is not seen by visitors in all industries. The page scroll rate in 2020 was 56.8%. Therefore, a large number of page views is not enough, the pages should be optimized so that users do not stop at half the page and do not skip content that can be valuable. The indicator that has the biggest impact on a business final performance is the conversion rate. The average conversion rate is 1.82%. The decline in e-commerce conversions in 2020 as compared to the previous period is due to the effects of the Covid-19 crisis: decreased consumer demand, lower consumer incomes, increased uncertainty. Conclusions and directions for further research. The main trends and problems of e-commerce in the world are identified and strategic guidelines for the future are presented, including: development of mobile commerce; wider use of the Online to Offline business model; development of electronic payment systems; supporting multichannel operations; personalization in digital marketing; increasing brand awareness; providing better quality information for customers; active promotion of innovations in e-commerce. The obtained scientific results can be applied in practice to optimize the work of online stores and to reduce costs by increasing the e-commerce efficiency. Further research in this area will address the rationale for e-commerce marketing strategy.