How to Build Secure, Scalable Code in ServiceNow (The Right Way) : A Must-Know for Devs & Architects

[BillMartin]

If you've ever struggled with keeping your data validation consistent, scalable, and secure in ServiceNow, you're not alone.

In many Script Include implementations, validation logic is duplicated across utility classes, services, or even GlideAjax processors. This not only leads to bloated code, but it also makes your application fragile — especially when dealing with complex integrations or REST API endpoints.

As a developer or architect building enterprise-grade solutions, here’s a better way: bring validation logic directly into your entity classes.

What We Did

We redesigned our EmployeeEntity class to handle both required field checks and data type validation right within its constructor — using a ValidationHelper. That means any time you create an instance of the entity, you automatically enforce:

• Required fields

• Correct data types

• Secure, clean input

Why This Matters

✅Code Reusability — No more duplicating validations
✅Security — Block bad or simulated attack data early
✅Data Integrity — Prevent garbage-in logic by design
✅Simplified Services — The business layer stays focused on logic, not cleanup
✅Cleaner Architecture — Validation lives where it belongs: in the object

Watch the Demo

I walk through the full implementation in this YouTube video, including the rationale, structure, and how it defends against malformed or malicious input:

Final Thoughts

If you’re working on ServiceNow backend architectures, start thinking about responsibility-driven design. Entities should own their data integrity. And services should only worry about business logic.

This pattern helps you scale cleanly — and defend your platform confidently.

Join the Conversation

Have you applied validation in entities before? What patterns are you using to enforce security and structure?

Drop your thoughts or improvements below. Let’s raise the bar for ServiceNow development together.