This paper presents a legal analysis of fulfillment services, aiming to develop a comprehensive understanding of their legal nature and define their place in the system of civil contracts. Using direct observation and analysis of primary and secondary sources, the article defines the concept of fulfillment services, defining the subject matter of the contract, the parties, and their legal status. As a result of this research, the author concludes that it is necessary to develop contractual relationships and a systemic understanding of fulfillment services as an element of e-commerce, since, despite its current popularity and widespread use, fulfillment services remain virtually unknown in judicial practice.