Azure multi-tier application architecture combining Azure Front Door, WAF, CDN, and Application Gateway to route external and internal traffic through a secure perimeter. The presentation layer hosts UI App Service and API Management, while the application layer runs API App Service and Timer Functions that integrate with on-premises Oracle Fusion and CIS systems via hybrid connectivity. Data layer includes Azure SQL with geo-replication, Azure Cache for Redis, and Storage Account, with identity managed through Azure AD, Okta federation, and Managed Identity for service-to-service auth. Observability spans Application Insights, Azure Monitor, and Log Analytics to track performance and security across all tiers. Fork this diagram to customize subnets, add ExpressRoute for on-prem connectivity, or adjust scaling policies for your workload.