Azure Application Gateway vs Azure Traffic Manager

 Azure Application Gateway and Azure Traffic Manager are both load-balancing solutions in Azure, but they serve different purposes and operate at different layers of the network stack.

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🔍 Quick Comparison

Feature	Application Gateway	Traffic Manager
Network Layer	Layer 7 (Application layer, HTTP/HTTPS)	Layer 4/7 (DNS-based redirection)
Load Balancing Method	Reverse proxy	DNS-based redirection
Use Case	Load balance within a region	Route traffic across regions
Protocol Support	HTTP, HTTPS (Web traffic)	Any protocol (DNS-based, so protocol-agnostic)
Geographic Routing	❌ (single region only)	✅ (multi-region and geo-based routing)
SSL Termination	✅ Yes	❌ No (doesn't touch actual traffic)
Web Application Firewall	✅ Built-in WAF	❌ No
Health Probing	✅ Application-level (URLs, HTTP status)	✅ Endpoint-based (simple HTTP checks)
Sticky Sessions / Affinity	✅ Yes	❌ No
Multi-region Failover	❌ No (used per region)	✅ Yes
Custom Domain Routing	✅ Path-based & domain-based	✅ Domain-based only (via DNS)

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🛠️ When to Use Each

✅ Use Application Gateway when:

• You need layer 7 load balancing within a single Azure region.

• You want to do SSL termination, cookie-based session affinity, or URL/path-based routing.

• You want to use Web Application Firewall (WAF).

• You’re deploying web apps (e.g., in App Services, VMs, AKS) behind a reverse proxy.

✅ Use Traffic Manager when:

• You want to route users to the closest or healthiest Azure region (e.g., for geo-redundant services).

• You need DNS-based global failover or performance-based routing.

• Your endpoints span multiple Azure regions, or even outside Azure.

• You're working with non-HTTP services (e.g., SMTP, FTP, custom ports).

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🔄 Can They Work Together?

Yes! In a high-availability architecture:

• Traffic Manager is used to direct global clients to the best region (e.g., East US or West Europe).

• Each region uses its own Application Gateway to manage and protect internal traffic.

🧭 Diagram:

                    User
                      |
           +---------------------+
           |  Traffic Manager    |
           +---------------------+
             /            \
   [App Gateway 1]     [App Gateway 2]
     (Region A)           (Region B)
         |                   |
    Web Apps/VMs       Web Apps/VMs

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🧠 Summary

You want to...	Use...
Load balance HTTP/HTTPS traffic in-region	Application Gateway
Distribute traffic across regions/globally	Traffic Manager
Route by URL or path	Application Gateway
Route by region or endpoint health	Traffic Manager

Let me know if you want help choosing for your specific architecture or a cost comparison.