Role of API gateways

An API gateway is a singular interface that handles all the incoming requests before redirecting to the internal servers. An API gateway typically provides the following functions:

• Routes the incoming traffic to the appropriate service hosted with the provider's data center/cloud. Provides a reverse proxy model to limit the exposure of various APIs and services hosted within the provider's data center/cloud.
• Filters all the incoming traffic from all kind of channels—web, mobile, and so on.
• Implements security mechanisms (such as OAuth) to authenticate and log the service usage.
• Provides ability to throttle and limit traffic to certain services.
• Transforms data between the service consumer and provider.
• Provides one or more APIs that map to an underlying service provider. For example, for different kind of consumers—mobile, web, paid service, or a free service, the same underlying service can be split into multiple custom APIs that are exposed to a different set of consumers, so that the consumer sees only the features it needs: