Amazon API Gateway is a fully managed service used for hosting HTTPS APIs on top of AWS. This service helps in creating, publishing, maintaining, monitoring, and securing APIs. It supports standard HTTP methods, and you can authenticate and authorize requests using services such as IAM and Conginito. Amazon API Gateway provides highly scalable parallel processing, DDoS protection, and features for throttling, metering, and capping usage for backend systems.

Its benefits include the ability to create a unified API frontend to multiple microservices and supporting multiple versions of the APIs (as we iterate through dev, test, and release of APIs). CloudFront distribution can created for the API at no extra charge, and the API gateway can be set up to cache responses. The backend can be implemented as a Lambda function or a HTTP endpoint, and it can be integrated with CloudWatch for monitoring.

Compared to implementing code for HTTP/HTTPS yourself, the API Gateway is a highly integrated service that scales automatically and can handle thousands of concurrent calls, while providing support for authorization, access control, monitoring, and API version management.