Objective: due to the rapid technological changes, digital economy and contractual relations determine law transformation and legislation development towards adaptation to prospective spreading and application of smart contracts in civil and commercial turnover. In this regard, the study focuses on determining the legal essence of smart contracts as a fundamental step towards the development of their timely and clear regulation.Methods: the research is based on the methodology of formal-legal and comparative legal analysis. It compares the current Bulgarian legislation with supranational legal sources and identifies the characteristic features of smart contracts as demanded instruments necessary for modern law and economy. The article also compares them with the classical understanding of contracts, making it possible to understand and define the nature of smart contracts more accurately.Results: it was determined that a smart contract is a software code in which the parties predetermine conditions under which the contractual relationship between them is created, modified and terminated. The research proved that the contract execution does not depend on the action or inaction of its parties, but rather on the occurrence of a predetermined condition (a certain fact relevant to the parties) under which the contract must self-execute. It was substantiated that the will of the parties cannot be changed or replaced because of the special way in which the smart contract is recorded in a distributed ledger. It is found that the fundamental problem of transferring the will from the legal language to the program code of the smart contract persists: if the will of the parties is incorrectly transferred to the program code, the smart contract may self-execute, but its execution will not be the result that the parties counted on.Scientific novelty: the analysis made it possible to compare the current national (Bulgarian) legislation and supranational (European) law. It revealed the vagueness of smart contracts regulation, both at the national and international level, and identified a number of issues in need of scientific and legal interpretation, which refer to the legal nature of smart contracts in view of the self-executing program code concept.Practical significance: the study can serve as a basis for further development of legislation towards its adaptation to the prospects of smart contracts spreading and application in civil and commercial turnover. It also allows an in-depth analysis of the smart contracts practice referring to such unsolved problems as accurate transference of the parties' will to the program code (translation of specific terms from the legal language into the smart contract program code), electronic identification of subjects - parties to the transaction and many other issues.
