Industrial Automatic Control Systems and Controllers Annotation << Back Conflict-free Replicated Data Types in the Implementation of Decentralized and Semi-decentralized Offline-first Applications A.N. Alpatov, S.A. Esaev With the gradual transition from WEB 2.0 to the new iteration of WEB 3.0, certain technical requirements for the software that will operate in the new environment are outlined. So one of the basic requirements of the new iteration of the Internet development, becomes the departure from the centralized structures of management and storage of data in the direction of the decentralized model in the development of distributed software systems. This model forms a new approach to the development of web applications, called decentralized applications (dapp). Under this transformation, and under the infl uence of distributed registry technologies, either the entire distributed web application, or only part of it, is moving to a decentralized model, which assumes that the entire execution environment of the basic application logic, as well as the stored data, will be placed on the client parts of the application. However, in the current environment, despite the rapid growth of distributed ledger technology and the emergence of industry open platforms that provide tools for developing decentralized applications, such as Hyperledger Fabric, Hyperledger Iroha, etc., there are some significant issues that limit application scalability, such as transaction and processing latency, which can lead to an overall decrease in application performance. One way to improve the availability and loading speed of decentralized and semi-decentralized applications is to introduce and implement an appropriate design pattern for Offline-first web application development methodology, and to use conflict-free replicated data types, which will resolve possible transaction confl icts when performing operations in multiple processes. This paper proposes an approach for implementing conflict-free replicated data types in Offline-first applications, which can be applied to the implementation of accessible web applications. A mathematical model and formal definition of the linearizability property in a distributed decentralized application is also given. Keywords: Offline-first applications, decentralized applications, dAPP, CRDT, LWW Map. DOI: 10.25791/asu.4.2023.1433 Pp. 27-36.