The microservice application programming interface (API) becomes a growing concern in the IT industry, as a result of the increasing usage of microservice architecture style. There exist many successful practices among companies, communities, and so on. In contrast, the related academic research is still at an early stage, where lacks an overview of technologies for the design, implementation and operation of microservice APIs, as well as a general picture of concerns. In this article, we try to fill this gap by eliciting the technologies and concerns on microservice APIs and establishing a microservice API description model, with the intention of aiding researchers to gain an overview of this field and find possible research directions, and helping practitioners to better understand microservice APIs and be aware of the existing approaches for daily work. Twelve academic papers and 38 gray literatures are selected and analyzed following the systematic literature review approach. Besides, we give our observations from this study. For researchers, our findings show the most cared concerns of practitioners, and our description model can be used as a reference for new theories, experiments, and future research dimensions. For practitioners, our study can be used as a guideline for microservices experimentation and a starting point for practice.

中文翻译：

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系统的灰色文献综述：微服务应用程序编程接口的技术和关注点

由于微服务架构风格的使用越来越多，微服务应用程序编程接口 (API) 越来越受到 IT 行业的关注。在公司、社区等之间存在许多成功的实践。相比之下，相关学术研究尚处于起步阶段，缺乏对微服务API设计、实现和操作技术的概述，以及关注点的总体情况。在本文中，我们试图通过引出微服务 API 的技术和关注点并建立微服务 API 描述模型来填补这一空白，旨在帮助研究人员对该领域进行概述并找到可能的研究方向，并帮助从业者更好地理解微服务 API 并了解日常工作的现有方法。12篇学术论文和38篇灰色文献按照系统文献综述的方法进行选择和分析。此外，我们给出了我们从这项研究中得到的观察结果。对于研究人员来说，我们的研究结果显示了从业者最关心的问题，我们的描述模型可以作为新理论、实验和未来研究维度的参考。对于从业者来说，我们的研究可以作为微服务实验的指南和实践的起点。我们的研究结果显示了从业者最关心的问题，我们的描述模型可以作为新理论、实验和未来研究维度的参考。对于从业者来说，我们的研究可以作为微服务实验的指南和实践的起点。我们的研究结果显示了从业者最关心的问题，我们的描述模型可以作为新理论、实验和未来研究维度的参考。对于从业者来说，我们的研究可以作为微服务实验的指南和实践的起点。