Multi-tenant 3-tier architecture for Securitas shared instance deployments, isolating web and mobile users through HAProxy load balancing and firewall enforcement in the DMZ. Application servers implement tenant separation at the app layer while sharing a single MariaDB master-slave replication pair for data persistence. This shared-instance model reduces operational overhead and infrastructure costs while maintaining logical tenant isolation through application-layer controls and backup automation. Fork and customize this diagram on Diagrams.so to adapt DMZ topology, add read replicas, or integrate additional external services like IdP and push notifications. Remote management via Terracom Support provides operational access to both application and database tiers.