关于API Gateway与自定义域名区域/边缘优化配置的咨询

Great question—this is one of those AWS configurations that feels confusing at first, but makes total sense once you unpack the separate jobs each setting handles. Let’s break this down step by step:

First: What Do the API Gateway Types Actually Do? #

Your API Gateway’s regional/edge-optimized setting defines how the gateway itself is deployed and accessed by default:

• Edge-optimized API Gateway: AWS automatically provisions a CloudFront distribution in front of your gateway. This is built for global users—requests hit the nearest CloudFront edge location first, then get forwarded to your gateway’s home region. It’s the default for public APIs serving users worldwide.
• Regional API Gateway: Deployed directly in your chosen AWS region, with no built-in CloudFront layer. This is ideal for traffic coming from the same region (like an ECS cluster or Lambda function in us-east-1 calling the gateway) or when you want full control over your own CloudFront setup.

Second: What About Custom Domain Types? #

The regional/edge-optimized setting for a custom domain isn’t tied to the gateway’s type—it defines how traffic routes to your gateway through that domain. Think of the custom domain as a separate entry point that can route traffic differently than the gateway’s default endpoint.

Why Mixing Makes Sense (and When to Do It) #

The independence here gives you flexibility to serve different user groups or meet specific performance/control needs:

1. Edge-Optimized Gateway + Regional Custom Domain #

• Use case: You have a global public API (so you use an edge-optimized gateway for worldwide users) but also have internal teams or services in the gateway’s home region. Giving them a regional custom domain lets them bypass CloudFront entirely, cutting down on latency for local traffic. For example:
  • External users hit api.yourcompany.com (edge-optimized domain) which routes through CloudFront.
  • Internal us-east-1 services hit api-us-east-1.yourcompany.com (regional domain) which connects directly to the us-east-1 gateway.

2. Regional Gateway + Edge-Optimized Custom Domain #

• Use case: You want the performance benefits of edge optimization, but you need to customize the CloudFront layer beyond what API Gateway’s built-in edge option allows (like custom WAF rules, granular caching policies, or sharing the CloudFront distribution with other assets like static websites). By using a regional gateway, you avoid AWS’s default CloudFront setup, then attach your own CloudFront-backed edge-optimized custom domain to the gateway. This way you get global edge caching and full control over the CloudFront configuration.

The Big Picture #

The two settings are independent because they solve different problems:

• The gateway’s type defines its core deployment and default access path.
• The custom domain’s type defines how traffic enters your system for that specific domain.

This separation lets you tailor access patterns for different user bases, rather than being locked into a single routing strategy for all traffic.

内容的提问来源于stack exchange，提问作者Mehran