# Microservice API Evolution in Practice: A Study on Strategies and Challenges

**Authors:** Alexander Lercher, Johann Glock, Christian Macho, Martin Pinzger  
**arXiv:** [2311.08175](https://arxiv.org/abs/2311.08175)  
**Date:** 2023-11-14  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2311.08175v1/

## Key points

- Researchers conducted 17 semi-structured interviews with industry practitioners to identify microservice API evolution strategies and challenges.
- Participants had an average of 10 years of practical experience and 4.5 years of experience with loosely coupled services.
- Member checking was utilized, with feedback from participants resulting in minor remarks incorporated into the findings.
- Participant selection was done through snowball sampling, leading to 20 interviews conducted with participants from 12 companies.
- The study focused on message exchange techniques and documentation practices in microservices.
- Six strategies and six challenges for REST and event-driven communication were identified in microservice API evolution.
- Challenges included change impact analysis efforts, ineffective communication of changes, and consumer reliance on outdated versions leading to API design degradation.
- Proposed solutions included automating change impact analysis and improving communication of changes as open research directions.

## Summary

In this study, the researchers aimed to identify microservice API evolution strategies and challenges in practice by conducting 17 semi-structured interviews with developers, architects, and managers in 11 companies. The participants were industry practitioners with an average of 10 years of practical experience and an average of 4.5 years of experience with loosely coupled services. The study utilized member checking by sharing the results with participants for feedback and validation, resulting in minor remarks from two participants that were incorporated into the findings. Participant selection was done through snowball sampling, contacting previous colleagues and asking them to forward interview requests to peers matching the study's requirements. A total of 25 colleagues were contacted directly, leading to 20 interviews conducted with participants from 12 companies. Three interviews were excluded from the results due to various reasons such as handling API evolution like internal source code changes or not introducing breaking changes to product APIs yet. The study focused on message exchange techniques used in practice and their corresponding documentation techniques, answering the research question of how developers exchange messages between services and document them. Interviews lasted between 52-92 minutes, conducted both online via videoconference and in person without noticeable differences in participant openness or involvement based on the mode of communication. Overall, the research findings identified six strategies and six challenges for REST and event-driven communication via message brokers in microservice API evolution. Strategies emphasized API backward compatibility, versioning, and close collaboration between teams while challenges included change impact analysis efforts, ineffective communication of changes, and consumer reliance on outdated versions leading to API design degradation. The study highlighted important problems such as tight organizational coupling and consumer lock-in resulting from these challenges along with proposed solutions like automating change impact analysis and improving communication of changes as open research directions.