Microservices vs API : How Do These Two Fare Together?

In today’s industries, software applications are built on a day to day basis. But, while building these software, developers always have to keep in mind, the architecture, implementation of the code and the UI which the user will use. So, the only way to make sure all these parameters are met is by using the microservice architecture and APIs’. So, in this article on Microservices vs API, I will discuss the following topics:

• What are Microservices?
  • Monolithic Architecture
• What are APIs’?
  • HTTP Methods
• Where are APIs’ used in Microservices?
• Differences Between Microservices and API

So, let us get started.

What are Microservices?

Microservices or most commonly known as Microservice Architecture is an architectural style to build applications. So, Microservices basically structure an application as a collection of small autonomous services, modelled around a business domain. Now, when you have a monolithic application, you will basically have all the functionalities stored in one place.

For example, if you consider an e-commerce application, then it will have mainly 3 functionalities. The functionalities could be:

• The customers’ information
• The products stored by the customer in cart
• The products available in the e-commerce application

Now, before microservices came into the picture, monolithic architecture was used.

Monolithic Architecture

Monolithic architecture is an architectural style in which all the functionalities or the required components would be inside one big block.  So, if you build the above application, using the monolithic style, then the architecture would look as below:

As you can refer from the above image, all the components of the application would reside in a single area. But, there are few challenges of the monolithic architecture because of which Microservices has become so popular in the market. So, if we refactor this application to Microservices, then there would be three services (Customer Service, Cart Service, and Product Service).

Now, before I tell you how can we refactor this application into Microservices, next in this article on Microservices vs API, let me give you an insight about APIs’.

What are APIs’?

Application Program Interface or most commonly known as APIs’ is a way through which you can make sure two or more applications communicate with each other to process the client request. So, you can understand APIS’ as a point of contact, through which all the services communicate with each other to process the client’s request and send the response.

Now, while building and using applications, we generally do CRUD operations. When I say CRUD operations, I mean that we create a resource, read a resource, update a resource and delete a resource. So, APIs’ are generally developed by using the RESTful style, and these methods are nothing but the methods of HTTP.

HTTP Methods

The methods associated with the HTTP actions are, as you can see in the below image:

The above methods help us standardize a way in which actions will be performed on various applications having different interfaces. Also, with the help of these methods, you as a developer can easily understand the inference of the actions taken across the different interfaces.

So, now that, you know what are APIs’, next in this article on Microservices vs APIs’, let us understand where are APIs’ used in Microservices.

Where are APIs’ used in Microservices?

Consider a scenario, where you have built the above-considered e-commerce application using Microservices. Them you will basically see three services, i.e. the customer service, cart service, and products service. Now, how do you think these services communicate with each other to process the client’s request?

Well, that is through the APIs’. So, each of these microservices will have their own APIs’ to communicate with the other services. Refer to the below image:

Now, even if one microservice, does not work, then the application will not go down. Instead, only that particular feature will not be working, and once it starts working, APIs’ can process the request again and send the required response, back to the client.

Alright, so now that you know about Microservices and API, let us next look into the differences between Microservices and APIs’.

Microservices vs API

The difference between Microservices and APIs’ is as follows:

Also, from the above example, it must be clear to you that APIs’ are a part of microservices and thus help these services in communicating with each other. However, while communicating with the other services, each service can have its own CRUD operations to store the relevant data in its database.

Not only this but while performing CRUD operations, APIs’ generally accept and return parameters based on the request sent by the user. For example, if the customer wants to know the order details, then product details will be fetched from the product service, the billing address and contact details will be fetched from the customer service, and the product purchased will be fetched from the cart service.

With this folks, we come to an end to this article on Microservices vs API. I hope you have understood what are microservices and APIs’ and how are APIs’ used in microservices.

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Got a question for us? Please mention it in the comments section of ” Microservice vs API” and I will get back to you.