Microservices vs APIs: What’s The Difference?

Microservices and APIs crop up a lot in the world of technology. And whether you’re browsing the web or having a casual conversion in the office, it’s important to understand what these buzzwords really mean. In this article, we’re going to define the meaning of both microservices and APIs, in plain English, and hopefully clarify the difference between them.

Understanding the Monolith

Before we dive straight into what microservices really are, it’s important to understand the problems they intend to solve.

In the old days of software development, many software applications were developed as a single code base – known as a monolith. These complex applications handle an array of functionality, which in turn creates a whole host of problems. Let’s explore some of these complexities that we’d run into if we were to develop a monolithic application.

Monolithic architecture – redhat

First up is scalability. Imagine we build a web application with a UI, some business logic, and database access all caked into one code base. It’s amazing, the boss loves it, it goes online, job done. Now, jump forward a few months and the website is really taking off. To keep up with demand, we need to deploy further instances of our monolithic application to serve our juicy content to potential customers. We may only need to boost one part of our application but instead, we’re forced to deploy a whole new instance. We’re deploying parts of our application which we don’t need, which costs us valuable time and resources.

Another flaw is being locked into our choice of technology. Say we’ve developed our application in Ruby, and now the boss wants us to incorporate an exciting new Python-based AI feature. As a result of our technology choices, we’re stuck in the mud and forced to go back to the drawing board. 🤦

Now, with the concept and flaws of monolithic code bases fresh in our minds, let’s explore the wonderful world of microservices.

Microservices to the Rescue

Simply put, unlike monolithic applications, microservices are decoupled, independent and small systems designed to handle one piece of functionality. This architecture pattern splits apart the complexities of software applications to create testable, maintainable and switchable services.

Microservice architecture – redhat

In contrast to our earlier example, if our microservice-based application gains popularity, we can scale single parts of the application. This increase in scalability helps cut the costs in running large VMs with unused bits of our application.

Additionally, our bosses pesky AI module easily integrates as a separate microservice. Whether we develop our microservices in Ruby, Python, Java or absolutely anything else, we have no concerns when it comes to glueing it all together.

As a result of reduced complexity, our microservices become more easily understandable. Consequently, this reduces errors as well as the amount of documentation required for the system; That’s a win for both the developer and anyone who has to maintain the application in the long run!

It all sounds a little too perfect..

While they sound great on paper, microservices do not solve every issue – and in some cases, a monolithic architecture may still be preferable. Some disadvantages of microservices include:

  • Increased latency between services – Your code is sprawled across servers the cloud, and it takes time to send data between them
  • Potential timeouts – Servers go down, it happens
  • We now have many more servers to manage than we did with our monolithic application

Monolithic and microservices architecture both have their advantages and issues. For a deeper dive into which to use, and when, this freeCodeCamps article is a great place to start.

So, How Does an API Differ?

An API, or Application Programming Interface, is basically a set of rules, or contract, for a user to interact with a service. And you guessed it, this is how we, as developers, can interact with microservices. So, think of the API as the door to the microservice. A well-written API is key to abstracting all of the intricate workings of the underlying service; As users, we don’t usually care how a service works, we just care that it does work.

Many APIs these days are written in a RESTful manner, and provide methods for the usual Create, Read, Update and Delete (CRUD) operations – which correspond to the common HTTP verbs:

  • GET – returns some data from the service
  • POST – delivers some data to the service
  • UPDATE – updates some data on the service
  • DELETE – removes some data from the service

The main advantage of creating the API in this way is the familiarity and consistency of a particular services door; New potential users will have a good idea about how to navigate the service with no prior knowledge.


In this article, we’ve covered the fundamental differences between microservices and APIs.

We started off with the concept of the monolith, understanding the flaws that a multi-functional piece of code can have. Next, we moved onto learning what a microservice really is, and how it avoids the complexities of monolithic architecture. Finally, we clarified what an API really is, and how it differs from the microservice.

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