Both AWS Global Accelerator (GA) and Amazon CloudFront use the massive AWS global network to improve performance for end-users, but they work in fundamentally different ways and solve different problems. Confusing them is one of the most common mistakes in AWS architecture discussions.
The Core Problem Both Solve
When a user in Sydney connects to your application running in us-east-1 (Virginia), their packets travel over the public internet — a network of routers operated by dozens of different ISPs, with variable congestion, routing inefficiencies, and no quality guarantees. AWS's global fiber backbone is faster and more reliable than the public internet. Both services get user traffic onto that backbone as quickly as possible.
Amazon CloudFront (Content Delivery Network)
CloudFront is a CDN — its primary mechanism is caching. It stores copies of your content at Edge Locations (400+ globally) close to users.
- How it works: A user in Sydney requests
image.png. CloudFront checks the nearest edge location. If the image is cached there, it is served immediately from Sydney — the request never reaches Virginia. If not cached, CloudFront fetches it from the origin over the AWS backbone and caches it for future requests. - Best for: Static assets (images, CSS, JS, videos), cacheable API responses, and HTTP/HTTPS workloads where reducing origin load matters.
- What it does NOT do: It does not help with truly dynamic, uncacheable content (e.g., a personalized API response that changes per user per request). For those, the cache miss still goes to origin.
- IP addresses: Users connect to the nearest CloudFront edge location's IP, which changes and is not static.
AWS Global Accelerator
Global Accelerator does not cache anything. It is a network path optimizer.
- How it works: AWS assigns you two static anycast public IP addresses. "Anycast" means the same IP address is advertised from multiple AWS edge locations simultaneously. When a user in Sydney connects to your anycast IP, their traffic is automatically routed to the nearest AWS edge location (via BGP routing). From there, it travels over the AWS private backbone to your application endpoint (an ALB, EC2 instance, or EIP) in your chosen region. The public internet is only used for the first mile — the "last mile" from user to the nearest AWS edge.
- Best for: Non-HTTP protocols (TCP/UDP), gaming (UDP), IoT, VoIP, or any scenario where you need static, fixed public IPs (e.g., for IP whitelisting by clients).
- Health checking and failover: GA continuously health-checks your endpoints and automatically reroutes traffic to a healthy region within ~30 seconds if an endpoint fails — making it useful for multi-region active-active or active-passive architectures.
Decision Framework
| Dimension | CloudFront | Global Accelerator |
|---|---|---|
| Primary mechanism | Content caching | Network path optimization |
| Protocols | HTTP/HTTPS only | TCP, UDP (any protocol) |
| Static IPs | No | Yes (2 anycast IPs) |
| Caching | Yes | No |
| Best for | Static/cacheable content | Non-HTTP, fixed IPs, multi-region failover |
| DDoS protection | AWS Shield Standard (free) | AWS Shield Standard (free) |
| Cost model | Per-request + data transfer | Per accelerator-hour + data transfer |
Simple Rule: If you want to cache and serve content closer to users, use CloudFront. If you want to accelerate the network path for any protocol, need static public IPs, or need automatic multi-region failover, use Global Accelerator.
Interviewers often present this scenario: "A gaming company needs low-latency UDP traffic for their multiplayer game, and their enterprise clients require static IP addresses for firewall whitelisting. Which service?" The answer is Global Accelerator — CloudFront only supports HTTP/HTTPS, and it does not provide static IPs. Global Accelerator's anycast IPs are fixed and can be whitelisted, and it supports UDP natively. Knowing that CloudFront is HTTP-only is the key differentiator.