Choose an API gateway by the rules it must enforce and the team's ability to operate it. The number of microservices alone does not determine the product.
Suppose a shop has order and customer services. Its first need may simply be to expose one address and forward each request to the correct service. Later, external partners may require separate credentials, usage limits and audit records. Those are different requirements and can lead to different choices.
1. Decide what belongs at the gateway
A gateway is the entry point that forwards requests and applies shared policies. For example, it can check that a caller has a valid token before sending an order request onward.
