When having a lot of microservices, discovery, location, integration, security, and analytics become a challenge. Then comes the need for the software service called API gateway. An API gateway addresses a number of concerns within the microservices architecture, and provides certain features which are useful in the implementation of the architecture.

Features commonly provided by an API gateway include the following, and are to be sought when deciding which API gateway to use in the implementation of your microservices architecture:

API Security: The API gateway controls the access to services for partners, customers, and employees (developers, DevOps, and so on). Some API gateways also provide features of API key management, payload inspection, and validation.

• Quality of service: API gateways provide features like throttling, restrictions, and routing on services as well as network level QoS monitoring.
• Unified services environment: Such features include addressing, mediation, and orchestration of microservices as well as translation of data formats and protocols. API gateways also expose the right API according to the right client trying to consume the API based on its own platform. For example, mobile, iOS, Android, web, and others.
• Policy management: API gateways enable policies to easily configure the API gateway and settings to control and protect deployed API services, and to provide segregated access to development, test, and production environments.
• Analytics: API gateways also provide API analytics of various kinds, which are able to generate reports and charts based on usage metrics for all services and also for the API gateway itself.