Amazon API Gateway Interview Questions and Answers for 7 years experience

Amazon API Gateway Interview Questions & Answers (7 Years Experience)
  1. What is Amazon API Gateway?

    • Answer: Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs at any scale. It acts as a reverse proxy, handling all the incoming API requests and routing them to the appropriate backend services (e.g., Lambda functions, EC2 instances, etc.).
  2. Explain the different API Gateway deployment stages.

    • Answer: API Gateway allows you to deploy your API to different stages (e.g., dev, test, prod). This enables you to manage different versions of your API concurrently, facilitating testing and deployment without affecting production. Each stage is an independent deployment with its own configuration and endpoints.
  3. How do you handle authentication and authorization in API Gateway?

    • Answer: API Gateway offers several ways to handle authentication and authorization: AWS IAM, Amazon Cognito, custom authorizers (Lambda functions), OAuth 2.0, and API keys. You can choose the method that best suits your security needs and application architecture.
  4. Describe different API Gateway request mapping templates.

    • Answer: Request mapping templates allow you to transform the incoming request before it's sent to the backend. You can use Velocity Template Language (VTL) to extract data from the request, add headers, modify the request body, etc. This is crucial for integrating with various backend systems that might require different request formats.
  5. Explain API Gateway response mapping templates.

    • Answer: Similar to request mapping templates, response mapping templates transform the response from the backend before it's sent to the client. You can use VTL to modify the response body, add headers, and format the output to match the client's expectations.
  6. How do you handle errors in API Gateway?

    • Answer: API Gateway allows you to define error handling logic using error mapping templates. These templates allow you to customize the error response returned to the client, based on the error code or type received from the backend.
  7. What are API Gateway integrations? Explain different integration types.

    • Answer: Integrations define how API Gateway connects to your backend services. Common types include: HTTP integrations (calling HTTP endpoints), AWS service integrations (e.g., Lambda, DynamoDB), and Mock integrations (for testing without a backend).
  8. How do you monitor API Gateway performance?

    • Answer: API Gateway provides detailed metrics through Amazon CloudWatch, including request latency, error rates, throughput, and integration latency. These metrics can be used to identify performance bottlenecks and optimize your API.
  9. Explain throttling and rate limiting in API Gateway.

    • Answer: API Gateway allows you to control the rate of requests to your API using throttling and rate limiting. This helps to prevent denial-of-service attacks and manage resource usage.
  10. How do you handle caching in API Gateway?

    • Answer: API Gateway offers caching to improve performance and reduce costs by storing responses from your backend. You can configure caching at the method level and control the cache TTL (Time To Live).
  11. What are custom authorizers and how are they used?

    • Answer: Custom authorizers are Lambda functions that you can use to implement custom authentication and authorization logic. They allow you to integrate with various authentication systems and enforce fine-grained access control.
  12. Explain the concept of API Gateway REST APIs vs. HTTP APIs.

    • Answer: REST APIs are the older, more feature-rich option, offering features like request/response mapping templates and more extensive customization. HTTP APIs are newer, simpler, and more cost-effective, suited for simpler use cases. They are generally faster and more lightweight.
  13. Describe how you would handle a large volume of API requests.

    • Answer: Strategies include using caching effectively, implementing proper throttling and rate limiting, optimizing backend services, using multiple API Gateway endpoints (regional distribution), and employing load balancing techniques.
  14. How would you debug issues with your API Gateway setup?

    • Answer: Use CloudWatch logs to analyze request and response details, integration logs, and error messages. Use API Gateway's testing tools to reproduce issues and examine request/response flows. Utilize CloudTrail for auditing and security analysis.
  15. How do you secure your API Gateway endpoints?

    • Answer: Employ robust authentication and authorization mechanisms (IAM, Cognito, custom authorizers). Use WAF (Web Application Firewall) to protect against common web attacks. Configure HTTPS for all communication. Regularly review and update security policies.
  16. Explain the use of API Gateway with serverless architectures.

    • Answer: API Gateway is ideally suited for serverless architectures. It acts as the front door, routing requests to Lambda functions, DynamoDB, or other serverless services, simplifying the management and scaling of the entire application.
  17. How do you deploy and update your API Gateway configurations?

    • Answer: Using the AWS Management Console, AWS CLI, or SDKs (Software Development Kits), you can deploy new configurations and update existing ones. Employing infrastructure-as-code tools like CloudFormation or Terraform enables automated deployments and version control.
  18. What are the costs associated with using API Gateway?

    • Answer: Costs vary based on the API type (REST, HTTP), number of requests, data transferred, and usage of additional features like caching and custom authorizers. Refer to the AWS pricing calculator for detailed cost estimations.
  19. Describe your experience with API Gateway's integration with other AWS services.

    • Answer: [Provide specific examples of integrations with services like Lambda, DynamoDB, S3, Cognito, etc. Detail the challenges and solutions encountered.]
  20. How do you handle different request methods (GET, POST, PUT, DELETE, etc.) in API Gateway?

    • Answer: API Gateway allows you to define different methods for each resource, associating each method with a backend integration and corresponding configurations for authentication, authorization, request/response mapping, etc.
  21. How do you manage different API versions using API Gateway?

    • Answer: Utilize deployment stages to manage different API versions concurrently. You can create separate stages for different versions (v1, v2, etc.) and route traffic accordingly. Versioning can also be achieved using different API names or path parameters.
  22. Describe your experience with using API Gateway with different programming languages for your backend integrations.

    • Answer: [Mention specific languages like Node.js, Python, Java, etc. Detail your experience integrating with each and any challenges faced.]
  23. Explain how you've used API Gateway's logging and monitoring capabilities to troubleshoot production issues.

    • Answer: [Describe specific scenarios where you used CloudWatch logs, metrics, and X-Ray tracing to diagnose and resolve API Gateway issues in a production environment.]
  24. How do you handle cross-origin resource sharing (CORS) in API Gateway?

    • Answer: API Gateway allows you to configure CORS settings at the method level, specifying which origins, methods, headers, etc., are allowed to access your API.
  25. What are some best practices for designing and implementing APIs using API Gateway?

    • Answer: Follow RESTful principles, use proper versioning, implement robust error handling, utilize caching effectively, secure your API with appropriate authentication and authorization methods, and thoroughly test your API before deployment.
  26. How do you manage API keys in API Gateway?

    • Answer: API keys can be created and managed through the AWS Management Console or the AWS CLI. They can be assigned to specific API stages and used for basic authentication. You can also set usage limits and quotas.
  27. Describe your experience with using API Gateway's request validators.

    • Answer: [Explain how you've used request validators to ensure that incoming requests adhere to predefined schemas and data types, preventing invalid requests from reaching your backend.]
  28. How have you used API Gateway to integrate with third-party APIs?

    • Answer: [Provide examples of integrations with third-party services and describe the approaches used, including handling authentication, data transformation, and error handling.]
  29. What are some common challenges you've faced while working with API Gateway, and how did you overcome them?

    • Answer: [Discuss specific challenges like debugging complex integrations, handling large volumes of traffic, optimizing performance, and security vulnerabilities. Explain your problem-solving approach in each case.]

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