Traditional network security models falter in cloud-native environments like Kubernetes, where components frequently change IP addresses due to scaling and updates. A zero-trust architecture addresses this issue by requiring authentication and authorization for every request, regardless of network location. This approach shifts how platform engineers design Internal Developer Platforms (IDPs), emphasizing security without hindering productivity. The key principle is "never trust, always verify," which is vital in dynamic environments where service identities can change rapidly. The article outlines several core principles of zero trust. First, verification occurs explicitly at each layer of the system using all available context, including request metadata and behavioral signals. For example, service-to-service authentication relies on cryptographic identities instead of IP addresses. This ensures that each step in a CI/CD pipeline has independent authentication, rather than relying on inherited trust from previous actions. Second, the concept of least privilege access allows users to have temporary permissions that automatically expire, reducing the risk of stale or forgotten credentials. Third, the architecture is designed with the assumption that breaches may occur, necessitating isolation of workloads and segmented access to minimize potential damage. Service identity plays a crucial role by providing cryptographic proof of a workload's identity, independent of its location. SPIFFE and SPIRE facilitate this by issuing short-lived X.509 certificates, which help establish secure connections between services without manual certificate management. Policy-as-code mechanisms, like OPA Gatekeeper, enforce compliance at deployment time, preventing security violations before they can impact the system. Runtime monitoring tools, such as Falco, provide an additional layer of security by detecting unexpected behavior after deployment. This dual-layer approach ensures that security is integrated into both the development process and operational oversight, separating policy creation from pipeline ownership to maintain agility while upholding standards.