How to solve the interaction problem of 100 microservices? What is an API Gateway and what does it do?

When interacting with a large number of microservices (for example, 100), managing relationships, routing, security, and API versioning becomes complex. To simplify this, an API Gateway is used — it serves as a single entry point for all client requests to microservices.

What does the API Gateway do:

• Routing requests to the necessary microservices.
• Data aggregation — it can combine responses from multiple services.
• Authentication and authorization — it checks access rights.
• Transformation of requests and responses — for example, changing data formats.
• Caching to improve performance.
• Rate limiting and DDoS protection.

Thus, the API Gateway simplifies client interaction with the system, hiding the complexity of the internal architecture and reducing the number of integration points.

Example: a client makes a request to the API Gateway, which then redirects requests to the necessary microservices, collects responses, and returns a unified result.