When designing API-based workloads, which pattern provides a fully managed serverless API fronting back-end services?

• A. Amazon API Gateway in front of Lambda (or other compute) backends
• B. CloudFront in front of API endpoints
• C. AWS AppSync
• D. Elastic Load Balancing with REST backends

Answer: (A)

Putting a fully managed API front end in front of your back-end services means using an API gateway to expose and manage your APIs without server provisioning. API Gateway provides a scalable, serverless surface that handles authentication, authorization, throttling, input validation, request/response transformation, and monitoring, while routing requests to Lambda or other compute back-ends. This pattern gives you a clean, low-ops API layer that scales automatically and integrates easily with serverless or containerized back-ends.

CloudFront is a content delivery network that can sit in front of endpoints but isn’t a full API management layer. AppSync focuses on GraphQL APIs, not general REST/HTTP APIs, and Elastic Load Balancing requires managing compute resources and isn’t serverless.