Amazon API Gateway is an AWS service for creating, publishing, maintaining, monitoring and securing REST, HTTP and WebSocket APIs. It acts as a front door for applications that access data, business logic or functionality from backend services, for example workloads on Amazon EC2, code on AWS Lambda or other web applications. It handles traffic management, authorisation and access control, monitoring and API version management, supports authentication through IAM, Lambda authorizers and Amazon Cognito, and integrates with AWS WAF. It is a fully managed cloud service.
Amazon is a US company, so the service falls under US jurisdiction, including the CLOUD Act. API Gateway is available in many AWS Regions, including Frankfurt, Ireland, Paris, Stockholm, Milan, Spain and Zurich, and APIs are created per Region. The product is not open source and has no self-hosted edition. Running APIs in a European Region keeps processing geographically in Europe, but the organisation still depends on a US provider.