23 ServiceNow Design Patterns Every Developer Should Know (Inspired by the Gang of Four)

[BillMartin]

Hi ServiceNow builders, architects, and curious tinkerers!

If you’ve ever wondered how to make your ServiceNow solutions more scalable, maintainable, and professional—this is for you.

In this post, I’ll walk you through how the 23 classic Gang of Four (GoF) design patterns map into real ServiceNow use cases, giving you a framework to architect better solutions across the platform—from scripting to integrations to app design.

Why Design Patterns Matter in ServiceNow

ServiceNow is not just a low-code platform—it’s a software engineering platform. If you’re writing Script Includes, managing integrations, or building scoped apps, understanding design patterns can drastically improve code quality and reduce technical debt.

These patterns offer battle-tested blueprints that help you solve problems with flexibility and elegance.

The 3 Categories of Patterns (with Examples)

Creational Patterns – Control how objects are created

• Singleton – For utility classes like LogManager or CacheHandler

• Factory Method – Dynamically return notification handlers (email, Slack, etc.)

• Abstract Factory – Generate UI Policies/Client Scripts for different modules

• Builder – Assemble complex GlideRecord data responses

• Prototype – Clone Catalog Items or Templates during provisioning

Structural Patterns – Organize objects and their relationships

• Adapter – Translate external API formats (e.g., Zendesk → Incident)

• Decorator – Add dynamic content to notifications (footer, disclaimer, etc.)

• Facade – Simplify CMDB operations in a single method call

• Composite – Manage CI relationships as tree structures

• Proxy – Cache third-party API calls in Script Includes

Behavioral Patterns – Define communication and logic flow

• Observer – Notify multiple systems when Major Incident updates

• Strategy – Switch SLA calculation logic dynamically

• Command – Encapsulate Flow Designer actions as reusable commands

• State – Change logic based on record state

• Chain of Responsibility – Implement multi-step approval processes

(Want the full 23 with context? Let me know and I’ll publish the extended version!)

Video Walkthrough Available

If you’re a visual learner, I’ve explained all of these in my new YouTube video:

Watch here: ServiceNow Design Patterns – Complete & Quick Start 

 

Final Thoughts

You don’t have to memorize all 23 patterns—but if you understand when and why to use them, your ServiceNow solutions will become more modular, scalable, and easy to maintain.

If this helped you, give it a thumbs up or drop a comment.
Have a favorite design pattern in your own projects? Share it below!