Identifying architectural technical debt, principal, and interest in microservices: A multiple-case study

Background: Using a microservices architecture is a popular strategy for software organizations to deliver value to their customers fast and continuously. However, scientific knowledge on how to manage architectural debt in microservices is scarce. Objectives: In the context of microservices applications, this paper aims to identify architectural technical debts (ATDs), their costs, and their most common solutions. Method: We conducted an exploratory multiple case study by conducting 25 interviews with practitioners working with microservices in seven large companies. Results: We found 16 ATD issues, their negative impact (interest), and common solutions to repay each debt together with the related costs (principal). Two examples of critical ATD issues found were the use of shared databases that, if not properly planned, leads to potential breaks on services every time the database schema changes and bad API designs, which leads to coupling among teams. We identified ATDs occurring in different domains and stages of development and created a map of the relationships among those debts. Conclusion: The findings may guide organizations in developing microservices systems that better manage and avoid architectural debts. (C) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).