What should you consider when defining boundaries between decomposed applications?

When defining boundaries between decomposed applications, it is essential to identify logical groupings of functionality based on business domains. This approach ensures that similar functionalities are aligned within a single application, allowing for better organization, clearer architecture, and more maintainable code.

Organizing applications around business domains facilitates an understanding of how different areas of the business interact, and it can help in mapping user journeys and workflows effectively. By keeping functionalities that serve similar purposes or target the same user groups together, it enhances coherence within the application and can improve performance as well, since related features often share data and processes.

In contrast, randomly assigning modules to different applications can create confusion and lead to a tangled architecture that is hard to navigate. Minimizing the number of applications solely for the sake of reducing complexity does not consider the functional needs and could potentially create monolithic applications that are cumbersome to update or scale. Likewise, avoiding dependencies between applications altogether may be unrealistic; some level of inter-application communication is often necessary, and managing these dependencies strategically is preferable to completely eliminating them.