Hybrid architectures for decentralised applications : an event‐driven approach

Abstract

The adoption of decentralised applications (dApps) in enterprise systems presents significant challenges and opportunities for hybrid architectures. Blockchain technology offers enhanced security, transparency, and immutability, all of which are essential for protecting sensitive data in enterprise‐grade applications. However, fully decentralised applications face several drawbacks, such as issues related to scalability, privacy and usability. Storing large amounts of data on the blockchain is infeasible, transparency means exposing sensitive data to risks and slow transaction speeds and higher latency hinder a smooth user experience. Hybrid architectures address these challenges by balancing the strengths of blockchain and centralised systems. By combining on‐chain and off‐chain storage, they enable larger capacity, faster data queries, and improved transaction times, making them compelling solutions for enterprise adoption. To realise these benefits, this project aims to demonstrate how an Event‐Driven Architecture (EDA) can enhance fault tolerance and responsiveness by enabling real‐time communication between blockchain and traditional components, as suggested in previous research on hybrid architecture design. The EDA approach integrates Command Query Responsibility Segregation (CQRS) with event sourcing, allowing CQRS commands to be mapped to blockchain transactions while CQRS queries are linked to blockchain calls. To validate this approach, a reference implementation is developed as a foundation for future developers, focusing on a pharmaceutical supply chain. The implementation begins with a fully decentralised application as a baseline, which is adapted into a semi decentralised system. This case study demonstrates the practical application of hybrid design, with key decisions including the selection of a framework supporting EDA principles and integration of message brokers. A qualitative analysis explores the feasibility of this architectural transition and examines the benefits identified in prior research. Additionally, a quantitative evaluation assesses the robustness and performance of the resulting hybrid system. The results confirm that hybrid architectures deliver the expected benefits, including improved scalability, enhanced system responsiveness, and greater resilience to failures. The implementation demonstrates more efficient event handling, reduced processing delays, and a smoother integration between blockchain and traditional systems, validating its effectiveness for enterprise adoption.