top 10 AWS API Gateway interview questions and answers

I can provide you with a list of top 10 AWS API Gateway interview questions and answers, which can be helpful for a Professional Cloud Developer experienced in working with AWS.

1. Q: What is AWS API Gateway and what are its main features?
   A: AWS API Gateway is a fully managed service that simplifies the creation, publishing, maintenance, and monitoring of RESTful and WebSocket APIs. The main features include caching, logging, security, custom domain names, throttling, monitoring, and API lifecycle management.
   
2. Q: What are the differences between REST APIs and WebSocket APIs in API Gateway?
   A: REST APIs are based on the HTTP protocol and follow the request-response model, whereas WebSocket APIs are bidirectional, real-time, and event-driven, allowing clients to send and receive messages at any time.
   
3. Q: How does AWS API Gateway handle security and authentication?
   A: API Gateway supports multiple authentication and authorization methods, including AWS Identity and Access Management (IAM) policies, Lambda authorizers, Amazon Cognito user pools, and client-side SSL certificates.
   
4. Q: What is the purpose of API Gateway caching and how does it work?
   A: API Gateway caching helps to improve performance by storing responses to API calls in a cache, reducing the number of requests to backend services. Cache settings can be customized, such as time-to-live (TTL) and cache capacity.
   
5. Q: How can you monitor the performance of an API in API Gateway?
   A: API Gateway provides metrics and logging through Amazon CloudWatch, allowing you to monitor and troubleshoot your APIs. Some key metrics include request count, error count, latency, and cache hits/misses.
   
6. Q: What is a Lambda function and how does it integrate with API Gateway?
   A: AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. Lambda functions can be integrated with API Gateway as a backend service to process API requests and return responses.
   
7. Q: What is the role of API Gateway in a serverless architecture?
   A: API Gateway is a key component of a serverless architecture, as it enables the creation of scalable and secure APIs that interact with serverless backend services like AWS Lambda, DynamoDB, or Amazon S3.
   
8. Q: How does API Gateway handle versioning and stages?
   A: API Gateway supports versioning by allowing you to create multiple deployments of an API. Stages are used to manage different environments (e.g., development, staging, and production) and can be associated with specific API deployments.
   
9. Q: What are API Gateway custom domain names and how do they work?
   A: Custom domain names in API Gateway enable you to use your own domain to serve your APIs. You can map a custom domain to a specific stage of your API, and use AWS Certificate Manager (ACM) to provision and manage SSL/TLS certificates.
   
10. Q: How can you control access to your API Gateway APIs?
    A: You can control access to your APIs using resource policies, IAM policies, Lambda authorizers, or Amazon Cognito user pools. These methods help to ensure that only authorized clients can access your APIs, and can be used to implement fine-grained access control.