SOLID Principles in Salesforce development

Salesforce Clean Code Design Patterns Architecture SOLID principles

Why Design Patterns Matter in Salesforce (And When to Use Them)

Why Design Patterns Matter in Salesforce

Let’s be real: Salesforce development is its own beast. Unlike traditional platforms, we’re constantly juggling governor limits, a multi-tenant environment, and a "clicks-not-code" philosophy.

As Apex developers, we often have to find a difficult balance: writing clean, organized code while staying strictly within the platform's execution limits to avoid errors like Too many SOQL queries: 101.

This is where design patterns and SOLID principles come into play. Think of them as a roadmap for writing code that’s easier to test, extend, and, most importantly, doesn't make you want to quit your job when you have to debug it six months later.

Solving the "Same Old" Problems

Design patterns aren’t about over-engineering: they’re about not reinventing the wheel. In the Salesforce world, they help us tackle classic headaches:

Trigger Chaos: Moving logic out of triggers and into structured frameworks.
Service Layers: Keeping business logic in one place so your LWCs and Batch jobs aren't repeating the same code.
Mocking & Testing: Writing tests that actually run fast because you aren't inserting 500 records just to check one if statement.

What Are the SOLID Principles?

The SOLID principles are five rules for object-oriented programming introduced by Robert C. Martin ("Uncle Bob"). While they’ve been the "gold standard" for decades, it's important to remember their roots.

The SOLID Breakdown

Principle	Core Concept	Salesforce Application
SRP	Single Responsibility	Keep Trigger Handlers separate from API/Service logic.
OCP	Open/Closed	Use `virtual` classes to extend logic without editing the original file.
LSP	Liskov Substitution	Ensure subclasses don't break logic when used in place of a parent.
ISP	Interface Segregation	Build small, specific interfaces instead of one "god" interface.
DIP	Dependency Inversion	Inject dependencies to make your Apex code 100% mockable.

Why Bother in Salesforce?

Salesforce orgs live a long time. Multiple developers (and consultants) will touch your code over the years. Without some ground rules, your Apex can quickly turn into a "God Class"—a 5,000-line monster that everyone is afraid to touch.

By leaning on these principles (with a healthy dose of common sense), you get:

Easier Maintenance: Small, focused classes are way easier to read.
Better Testing: When you decouple your logic, you can use the Stub API to mock dependencies and make your tests lightning-fast.
Less Technical Debt: You won't have to rewrite your entire integration just because the vendor changed their API format.

The Bottom Line

Design patterns and SOLID principles aren't just academic concepts borrowed from "traditional" software engineering. They are practical tools that help us build apps that last.

The goal is a maintainable system, not a perfect diagram. Use what works for your org's scale, and don't be afraid to keep it simple when the situation calls for it.