Both have a distinct role in software development. However, having the overlap between the two, it becomes confusing to understand how they really differ. So, today’s article will guide you through the concept of APIs and microservices separately, what they do, the way they work, and how they differ from each other.

What are Microservices?

Microservices or Microservices Architecture is an architectural method that structures an application as a collection of smaller components also known as services that are loosely coupled, independently deployable, highly maintainable and testable, owned by a small development team, and organized around business capabilities.

Moreover, microservices allows frequent, reliable, and rapid delivery of extended, complex applications. The core reason behind the popularity of microservice architecture is its ability to build, integrate, and manage applications easily. It allows developers to build applications step by step and later work on each service separately without affecting the functionality of other services.

Why Use Microservices?

To understand the use of microservices, it is necessary to understand its predecessor - monolith architecture.

A monolithic architecture is a traditional model to design a software program in which all the functionalities reside under one large block. It means, all the components of the application such as the UI layer, data access layer, and the business logic layer remain in one storage. It becomes difficult to add new features or functionality to the codebase because of its large and complex architecture. Simply put, everything inside a monolithic architecture is so connected that it certainly becomes difficult to untangle.

Compared with Monolithic Architecture, Microservices prevails:

• Simplicity: To understand one perspective of the application, a developer does not have to understand the entire application.
• Robustness: As the application is divided into multiple services, even the failure of one will not negatively impact the entire software.
• Updates: Similarly, updating a part of the application doesn’t require the modification of a complete system that saves money, time, and the effort of debugging.
• Security: If one service somehow gets compromised, it will not harm other services.
• Flexibility: It is independent of the programming language and framework a development team uses for certain services of the application as it will not affect others.

Overall, by separating responsibilities, microservices simplify and accelerate the development process of the software. “But how will the collection of isolated modules interact and work simultaneously?” - you may ask. That’s where API comes into the role.

What is an API?

An API or Application Programming Interface is a tool for communication of services with each other in the microservice architecture which might differ in construction and function. An API cannot do anything unless connected with services and microservices like Function as a Service (FaaS), Software as a Service (SaaS), and Database as a Service (DBaaS). APIs are like doorways that help both developers and users to interact with the software. One can acknowledge API as a point of contact through which all the services communicate to process a client’s request and give an appropriate response.

Why Use API?

APIs provide a secure way to request and share content, services, and functionalities with both internal and external users. Without APIs in our toolbox, microservices might not exist.

For example, you are shopping online and want to check out. There’s an option to pay through GPay and you already have an account there with payment info setup. How Convenient, right?

Since Google pay is a different company from the online store you are on, an API will facilitate the interaction between the store and GPay. Here, the API on the store will request access to payment information. Now, the API on GPay will store the request, validate it, collect the information from the database and finally send it to the store to complete the transaction.

Not only for the third-part applications but APIs are also being used for interacting with the microservices of the application. It increases the usability and exposure of the service. An API simplifies the complexity to use the data inside other services while providing an easy way for the developers to access the required data. It acts as a lightweight solution for individual microservices to interact with each other.

APIs usually send data by HTTP requests and return a textual response in JSON format that can be used by developers as per their needs. Some of the API design styles one can use are SOAP, REST, GraphQL and so on.

Microservices VS API

An API is a communication channel between services that enables clients to use the underlying services of an application. While a microservice is an architectural design that divides an application into small, small-containing services making it easier to build and maintain software.

Although both are different from each other, they are usually paired together as the services under the microservices architecture uses APIs to communicate with each other. Within an application based on microservices, each service owns a separate API that determines what requests it receives and the way it responds to it.

An important thing to notice here is that no microservices are alike and each one of them uses APIs differently. Some might assign one API to access different services or multiple APIs to one service.

Lastly, APIs are not limited to microservices, it has uses far beyond it. They can be used to share data among systems in the web application or used internally without microservice implementation.

If you are a business owner who wants to develop their application or software on microservices architecture, then you must hire developers who are experienced and can provide prominent solutions. On the other hand, if you are a developer then you should focus on microservices and APIs even more as they can be highly useful for your future project.

Source: Decipher