Write Once, Enforce Everywhere: Reusing Rego Policies Across Build and Runtime

In most organizations, security and compliance are enforced twice — once during build-time checks and again at runtime through admission controllers and monitoring systems. Often, the policies written at build-time are not reused at runtime, leading to drift, redundancy, and gaps in enforcement. With the rise of Open Policy Agent (OPA) and Rego, teams now have the opportunity to unify policy logic and reuse it seamlessly across both phases. 

This article discusses the principles, design patterns, and practical techniques for reusing Rego policies at build-time and runtime, helping teams reduce duplication, improve compliance confidence, and accelerate software delivery.