Custom Domain Names & Edge Optimization

When you deploy an API Gateway API, AWS provides a default URL. It looks something like https://abcdef123.execute-api.us-east-1.amazonaws.com/prod.

While functional, this URL isn't very user-friendly or brandable. This lesson shows how to use your own domain name!

Every API Gateway API automatically gets a unique endpoint URL. This URL includes a random ID, the AWS region, and amazonaws.com.

• Example: https://{restapi_id}.execute-api.{region}.amazonaws.com/{stage_name}
• It works immediately after deployment.
• Great for testing, but not ideal for public-facing APIs.

Using a custom domain name for your API offers several advantages:

• Branding: Use your company's domain (e.g., api.yourcompany.com).
• Memorability: Easier for users and developers to remember and type.
• Flexibility: You can change your backend API without changing the public URL.
• SEO (for web APIs): Helps with search engine optimization.

Before you can use a custom domain, you need an SSL/TLS certificate. This certificate encrypts communication and proves your API's identity.

• AWS Certificate Manager (ACM) can provision free public SSL certificates.
• You can also import your own certificate.
• The certificate must be in the US East (N. Virginia) region for edge-optimized APIs.

Once you have an SSL certificate, you can configure your custom domain in the API Gateway console.

You'll specify your domain name (e.g., api.example.com) and associate it with the ACM certificate. API Gateway will then create a domain name and provide a DNS target (a CloudFront distribution domain name).

A custom domain needs to know which API Gateway API to route requests to. This is done using base path mappings.

You define a base path (e.g., /v1 or /) and map it to a specific API Gateway API and stage (e.g., prod).

• api.example.com/v1 -> my-api/prod
• api.example.com/users -> users-api/prod

The final step is to update your domain's DNS records. You need to create a CNAME record (or A record if using Route 53 alias) that points your custom domain to the DNS target provided by API Gateway.

This tells the internet that requests for api.example.com should go to the API Gateway's CloudFront distribution.

API Gateway offers different endpoint types. Edge-optimized endpoints are the default for REST APIs and are designed for global clients.

They use Amazon CloudFront, AWS's content delivery network (CDN), to route requests through the nearest edge location to your users.

This reduces latency and improves performance for geographically dispersed clients.

When you use an edge-optimized endpoint:

1. A user's request hits the nearest CloudFront edge location.
2. CloudFront forwards the request to your API Gateway in the AWS region.
3. The response is cached at the edge location (if configured) and returned to the user.

This caching and proximity routing significantly speeds up API calls for global users.

API Gateway also supports Regional endpoints. These are best when all your API consumers are in the same AWS region as your API.

• Edge-Optimized: Default for REST APIs, uses CloudFront, best for global users.
• Regional: Best for clients in the same region, can be fronted by your own CloudFront distribution for more control.

HTTP APIs only support Regional endpoints by default, but you can add CloudFront yourself.

You want to use api.mydomain.com for your API Gateway API, which will be accessed by users worldwide. Which of the following statements is TRUE?

In this lesson, we learned how to give your API Gateway APIs a professional, branded look using custom domain names. We covered the steps from SSL certificates to DNS configuration.

We also explored edge-optimized endpoints, understanding how they leverage CloudFront to deliver your API with low latency to users across the globe. You now know when to choose between edge-optimized and regional endpoints.