Blockchain/distributed ledger is a disruptive technology that provides the infrastructure for the development of decentralized applications and enables the emergence of new business models. Over the past few years, blockchain technology has attracted great interest from academia, developers, and startups, so many solutions have been developed to address the limitations of blockchain technology and meet the needs of software engineering.

The paper provides an overview of distributed ledger solutions, analyzing the problems faced, existing solutions, and the role of this technology in the development of decentralized applications. This study reviewed more than 100 papers on blockchain and drew on the ideas of startups, proposed a three-tier architecture for decentralized applications, and used this architecture to systematically classify various solutions.