How Non-Functional Requirements Should Drive System Architecture Decisions

Software engineer Anton, who is migrating a PHP monolith into Go microservices, argues that architectural decisions like CQRS or microservices versus modules are not matters of preference but are determined by non-functional requirements. He contends that any design debate lacking a traceable requirements line is merely a comparison of personal preferences. In his current Go services setup, a requirement noting that reads and writes differ in volume, shape, and failure modes directly produced a two-layer database architecture separating repository reads from manager writes. This package layout, measured across 2,733 Go files and 252 packages as of August 2026, naturally yields small, focused files without explicitly mandating brevity. The tradeoff is added structural overhead on every feature, but it enables the read and write paths to be independently changed, measured, and reasoned about.