Software Architecture in ServiceNow

[BillMartin]

When I first explored ServiceNow, I wasn’t looking for software architecture. I was just trying to make things work.

It started with a few client scripts and business rules. Forms, workflows, quick fixes. But as projects grew and more teams relied on what I built, I began to feel the friction. Things didn’t scale. Logic became duplicated.

Update sets clashed. Performance degraded. That’s when I realized the issue wasn’t my coding skills. It was the lack of a structured architectural approach.

ServiceNow is more than just an ITSM tool. It is a platform. And like any platform that enables full-stack development, ServiceNow demands software architecture, especially when you are designing reusable, scalable, and secure enterprise solutions.

Unlike traditional software development frameworks, ServiceNow does not enforce one architectural style. It does not follow MVC rigidly. It is not purely REST based or event driven either. Instead, it gives you the freedom to define your own patterns. And that freedom can become overwhelming if you don’t approach it with structure.

Architecture in ServiceNow takes form across several layers. The presentation layer includes the Service Portal, Now Experience components, and form based interfaces. This is where user interaction happens, supported by Client Scripts, UI Policies, and widgets.

Then comes the client server interaction layer, where GlideAjax, REST APIs, and asynchronous communication form the bridge. Understanding when and how to use these properly is critical to performance and user experience.

The business logic layer is the brain of your application. It includes Script Includes, Business Rules, and Flow Designer. A well designed business logic layer is modular, loosely coupled, and reusable across applications.

Underneath that is the data access layer. GlideRecord usage, data policies, and query rules define how data is fetched, validated, and stored. Misuse here can lead to performance bottlenecks, inconsistent data, or security gaps.

Integrations form another architectural concern. Whether using IntegrationHub, MID Server, or direct API endpoints, integration must be thoughtfully designed, secured, and monitored.

And finally, the governance layer wraps everything. Scoped applications, source control, update sets, ACLs, and CI CD practices provide lifecycle and compliance controls over your codebase.

But all of this structure needs one more thing to truly hold it together. That is confidence. Confidence that your changes won’t break what is already working. Confidence that refactoring won’t destroy functionality. This is where Test Driven Development comes in.

Test Driven Development is not yet widespread in ServiceNow, but it is possible and increasingly necessary. By writing tests before writing logic, you design for outcomes. You anticipate edge cases. You enforce contracts between layers. And when tests run automatically with every deployment, they give your architecture a safety net.

Instead of pushing changes and hoping for the best, TDD allows you to move fast without breaking things. It encourages better design, clearer code, and more maintainable systems. You shift from reactive debugging to proactive engineering.

Once I adopted architectural thinking combined with TDD principles, everything changed. I stopped writing isolated scripts and started designing testable, modular systems. Update sets became cleaner. Reuse became easier. Regression issues dropped significantly. Most importantly, I could collaborate confidently and scale solutions across business units.

If you are building anything beyond a single use solution in ServiceNow, you are already practicing architecture whether you realize it or not. The real question is, are you being intentional about it?

To help others navigate this journey, I created a complete YouTube playlist that walks through architectural principles, scripting patterns, and how to shift toward testability and modular thinking in ServiceNow development.

Start your journey now with the ServiceNow Architecture and Scripting Series on YouTube. It is a practical, hands on walkthrough with real examples and clear guidance.

Visit the playlist here

If you are midway through your ServiceNow journey and not sure how to scale your skills, this playlist also outlines a learning roadmap from beginner to advanced. Follow the roadmap to align your development work with scalable and sustainable practices.

And if you are finding value in the series, consider subscribing or joining as a member. Your support helps keep the content free and accessible to other ServiceNow learners across the globe.

Thank you for reading. Let us continue to build with intention, architect with clarity, and test with confidence.