Application Gateway
Definition
Azure web traffic load balancer with application-level routing, security features, and SSL termination for enhanced performance and security.
Use Cases
- Microsoft: Protecting and routing inbound web traffic for Azure-hosted applications — Uses Azure Application Gateway and Application Gateway WAF as part of Azure reference architectures to publish web apps with TLS termination, path-based routing to backend pools, and WAF policies for OWASP protections. (Improved security posture for internet-facing apps (reduced exposure to common web attacks) and simplified operations by centralizing routing and TLS/WAF controls.)
- Adobe: Routing HTTPS traffic to different backend services for web applications — Uses Azure networking patterns that commonly include Application Gateway for Layer 7 routing, TLS offload, and integration with Azure services (for example, routing to separate backend pools for different app components). (More flexible traffic management and easier scaling of independent backend components behind a single entry point.)
Provider Equivalents
- AWS: AWS Application Load Balancer (ALB)
- Azure: Azure Application Gateway
- GCP: Google Cloud HTTP(S) Load Balancing
- OCI: OCI Load Balancer (Layer 7 features via HTTP/HTTPS listeners and routing policies)
Frequently Asked Questions
- What's the difference between Azure Application Gateway and Azure Load Balancer?
- Azure Load Balancer works at Layer 4 (TCP/UDP) and routes traffic based on IP and port. Application Gateway works at Layer 7 (HTTP/HTTPS), so it can make routing decisions based on the URL path or hostname (for example, /api vs /checkout) and can provide web-specific features like TLS termination and Web Application Firewall (WAF).
- When should I use Azure Application Gateway?
- Use it when you need HTTP/HTTPS-aware routing (host-based or path-based), TLS termination/offload, session affinity, end-to-end TLS, or WAF protection for a web app. It’s a good fit for microservices and multi-site apps where different URLs should go to different backend services, or when you want a single, controlled entry point for multiple web workloads.
- How much does Azure Application Gateway cost?
- Pricing depends on the SKU (for example, Standard_v2 or WAF_v2), the number of gateway instances/capacity units used, and data processed. WAF-enabled SKUs cost more than non-WAF. Costs can increase with higher traffic, more scaling, and additional features (like WAF policies). For exact numbers, use the Azure Pricing Calculator and select the region and SKU you plan to run.
Category: networking
Difficulty: intermediate
Related Terms
See Also