Abstract
Microservices have become the de facto choice for large, complex systems, due to their drivers of cohesion and decoupling. According to this architectural style, the system is divided into small, independently deployable units, called microservices. In the literature, there are several architectural patterns for this style. Despite this, little is to be found focusing on extensibility. Further, in previous works, we analyzed the trade-offs involving some of those patterns, and among other findings, we identified some issues regarding extensibility in some cases. In the current work, we aimed to analyze how patterns affect the extensibility of microservice-based systems. We considered three specific approaches to extensibility: Microservice Internal Flexibility, Microservice Extensibility, and System Extensibility. We found 91 patterns in the literature, and analyzed 18 of them, of six different categories. The outcomes of this analysis are hoped to be useful for bringing extensibility as a key quality attribute when designing microservice-based systems.