Building Moduliths That Last: Patterns for Sustainable Module Integration

A system does not need to be distributed to have clean architectural boundaries. Moduliths (modular monoliths) have emerged as a popular alternative to microservices - But doesn't that mean we're going back to where we started from? Won't today's moduliths end up as Big Balls of Mud again in a few years? The key to a sustainable modulith is clean integration between modules. The shared runtime offers more integration options but also creates the temptation to take shortcuts and create a hot mess. This talk compares different approaches to integrating modules in a modulith. We will explore how different domains suit specific patterns better than others, and distill that knowledge into practical heuristics. We will also examine tactics for establishing these patterns in existing codebases. As a developer or architect, you will leave with a toolkit of modulith integration patterns and antipatterns, guidelines for choosing the right ones, and the knowledge to establish them in legacy applications.