API gateways manage microservices communication by acting as a single entry point for clients to interact with various microservices. They route requests, manage traffic, and handle load-balancing while providing additional features like authentication, logging, and rate limiting. By consolidating these functions, API gateways improve security and simplify client interactions, making it easier to maintain and deploy large-scale applications. This is crucial for achieving the scalability and reliability that microservice architectures intend to provide.