Application Integration

Role of APIs in microservices


Microservice architecture is revolutionizing the way enterprises build their technical infrastructure and develop new applications. They are helping a number of organizations to minimize the time required for software application projects and to maximize the reliability of backend systems. It is a key factor in the success of various Web-native businesses and is quickly spreading to more established enterprises, especially those currently focused on innovation, the application economy and digital transformation. Once you’ve decided microservices are right for your organization, keep the strategies discussed here in mind as you make the switch.

In 2017, we saw Organizations Bridge the gap between microservices and traditional systems with APIs to promote development speed and agility.

APIs play a crucial role in facilitating microservices.

For a microservice architecture to function, the infrastructure’s components must be able to interact. Each individual microservice must be able to communicate with every other microservice in the architecture as well as with the applications and Web sites they power and the databases from which they draw real-time information, essential to their functioning.
A successful microservice architecture requires APIs defined for communicating between individual services.

Therefore, each microservice must have an interface, which is why the API is a vital enabler of microservices. Only when you have well-defined APIs as the communications path between services can you truly take advantage of the team scaling capabilities that microservice architectures offer. Being based on the open networking principles of the Web, RESTful APIs provide the most logical model for building interfaces between the various components of a microservice architecture. In order to better expose services via APIs, a common interface for these APIs needs to be present to tell exactly what each service is supposed to do. Here are some common ways APIs and Microservices combination will enable eco-systems and fuel innovation.

Design First approach

Because microservice architecture is predominantly an enterprise-grade motion, and as such, it’s important to give APIs exposing the microservice data the first-class treatment. Many organizations have adopted a Design First approach to building microservices, which involves designing and defining the interface of the microservices first, reviewing and stabilizing this contract, and only then implementing the service. The Design First approach ensures that your services are compliant with the requirements of the client up front before any actual development has taken place.


As Enterprise adopt microservices at a rapid pace, Security Architects will start losing control and visibility of these services and APIs. Security breaches will be more prevalent and communication other issues that may have been previously implicit are now forced out into the open. However, API Gateways in microservices can solve these issues by standing in between as an abstraction layer that sits on the execution path of every request that goes to one of these microservices.

Data Orchestration

Each and every microservice in your system must have a well-defined and documented API. This API is the “contract” that exists between different service owners. API Management vendors like Axway have understood this pain for a while and added capabilities to their offerings, for example, Axway API Builder–in order to support non-tech people to rapidly build better APIs and run them.

Public and private APIs

Public APIs are used to communicate commitments on functionality and performance between an application and the people who consume that application. Private APIs are used to communicate commitments on functionality and performance within individual development teams that own different services within the larger application. These internal APIs are just as important as the public APIs your company exposes. One notable area where public and private API differs is in security and enforcing of service limits and constraints. The need for security and service limits is obvious for public facing APIs, but what about private APIs? It is easy to dismiss security and service limits as not important for private APIs. After all, the consumers of your private APIs and the owner of those APIs all work for the same company and presumably have the same goals and commitments. While this is generally true, there are still reasons why you may want to deploy an API Management solution to help automate authentication, authorization, and service limits for both your private APIs and public APIs.

As microservices based on emerging technologies such as containers or more mature Java programming tools continue to evolve, API Management is becoming more critically important. Each microservice generates its own API that needs to be maintained as each microservice gets continually updated.

That requires an API Management solution that can support all levels of API call activity that once would have been assumed to be unimaginable. Learn more here.