# Understanding Separation of Concerns (SoC) in NestJS

August 19, 2025 · 1 min · 78 words · Saurav Dhakal

When building applications, one of the most important design principles to keep in mind is Separation of Concerns (SoC). NestJS, with its modular architecture, makes applying SoC almost effortless — but understanding why it matters and how to use it properly will help you write cleaner, testable, and future-proof code.

## What is Separation of Concerns and Why it Matters?#

The basic idea is:

> A program should be divided into distinct sections, where each section addresses a single responsibility.