Stop Joining Tables In Your “Modular” Monolith

This article warns against the common practice of joining tables across module boundaries in a modular monolith. It argues that even with clean code separation, database joins between modules like Sales and Warehouse create hidden coupling that undermines the architecture. The author explains how a simple query to show inventory on an order page can weld two modules together, making them dependent at the data level. The article advocates for avoiding such cross-boundary queries to maintain true modularity, despite the initial convenience and speed of a join. It is a technical guide for software architects and developers on maintaining loose coupling in monolith designs.