# Software Engineering Applications Enabled by Blockchain Technology: A Systematic Mapping Study
###### Abstract  
The novel, yet disruptive blockchain technology has witnessed growing attention, due to its intrinsic potential. Besides the conventional domains that benefit from such potential, such as finance, supply chain and healthcare, blockchain use cases in software engineering have emerged recently. In this study, we aim to contribute to the body of knowledge of blockchain-oriented software engineering by providing an adequate overview of the software engineering applications enabled by blockchain technology. To do so, we carried out a systematic mapping study and identified 22 primary studies. Then, we extracted data within the research type, research topic and contribution type facets. Findings suggest an increasing trend of studies since 2018. Additionally, findings reveal the potential of using blockchain technologies as an alternative to centralized systems, such as GitHub, Travis CI, and cloud-based package managers, and also to establish trust between parties in collaborative software development. We also found out that smart contracts can enable the automation of a variety of software engineering activities that usually require human reasoning, such as the acceptance phase, payments to software engineers, and compliance adherence. In spite of the fact that the field is not yet mature, we believe that this systematic mapping study provides a holistic overview that may benefit researchers interested in bringing blockchain to the software industry, and practitioners willing to understand how blockchain can transform the software development industry. software engineering; blockchain technology; smart contracts; systematic mapping 2021 11  
(SE). In 2017, [PERSON] et al. [6] identified the need for specific software engineering practices that consider the distinctive properties of blockchain and coined the term blockchain-oriented software engineering (BOSE). These authors revealed the following BOSE challenges: the need for new professional roles, specific methodologies to ensure security and reliability, new modeling languages, and specific metrics adapted to BOSE, e.g., metrics to measure complexity, resource consumption and performance of such systems. In 2018, the need for the new discipline of BOSE was also advocated by [PERSON] et al. [7]. According to these authors, the reliance on smart contracts on a non-standard software lifecycle, poses issues, such as the difficulty in updating delivered applications or resolving bugs by releasing a new software version. These issues call for BOSE to contribute to testable and reliable smart contract software development. In fact, [PERSON] [8] called attention to the bi-directional relationship between software engineering and blockchain technology. [PERSON] [9] also emphasized the importance of cross-fertilization between software engineering and technologies that are hyped, such as machine learning and blockchain technology. Despite the fact that several secondary studies have examined the wider use of blockchain technology, they do not specifically examine its use in improving SE activities. In this paper, we aim to provide a holistic and comprehensive overview of emerging SE applications enabled by blockchain technology. To address this goal, we carried out a systematic mapping study that categorizes research studies according to their contribution, research type and topic. The latter refers to SE knowledge areas where blockchain has been introduced. Finally, we discuss the main findings in order to identify opportunities for future research in the SE field. Therefore, this study can be of interest to two main readers: researchers interested in bringing blockchain to the software industry in the form of applications, and practitioners willing to understand how blockchain can transform the software industry. The remainder of the paper is structured as follows: In Section 2, a review of the SE, blockchain technologies, and related works is presented. Section 3 describes the research design adopted for this study.