<![CDATA[Real-time enterprise platforms continuously deliver information to users and services, creating a need for access-control decisions that remain valid throughout event delivery rather than only at the time of an initial request. This article proposes a Zero Trust access architecture for real-time, event-driven enterprise platforms, in which subscription authorization is treated as a distinct access-control decision with a lifecycle that includes authorization, cached delivery, revalidation, and invalidation. The proposed architecture integrates identity and authorization services, API gateways, policy decision and enforcement points, role- and attribute-based access control, workload identity for background services, and centralized auditing. A defined threat model specifies the security conditions the architecture addresses, including unauthorized subscriptions, privilege changes during active delivery, stale authorization states, and misuse of service identities. The approach combines a layered reference architecture, a worked subscription lifecycle, explicit policy and enforcement logic, and a microbenchmark comparing per-event policy evaluation with precomputed entitlements on a single-host test environment. The benchmark indicates that moving routine authorization decisions outside the event-delivery path reduces per-event authorization cost by more than two orders of magnitude. However, the result is based on a single, unreplicated run per strategy and therefore provides an architectural indication rather than stable performance evidence or production-scale validation. Clinical monitoring is used as the primary application context, with financial risk processing, insurance claims routing, and specialty pharmacy fulfillment as supporting examples. The proposed architecture provides a structured basis for implementing continuous authorization in real-time enterprise platforms while preserving explicit security controls, supporting authorization-state changes throughout active subscriptions, and limiting authorization overhead within event-delivery paths]]>
