Microservices vs APIs: What's the Difference

Regarding software solutions, the only two solutions that strike first in every individual's mind are Microservices and APIs. These solutions are gaining popularity in the world of software development because of the constantly growing requirement to produce scalable, flexible, and secure applications at quicker turnaround times.

Customers' demands are changing rapidly, and their expectations from software solutions are to provide them with convenience and simplify their tasks.

The traditional single-path approach implements a lot of restrictions on the developers. Hence the developers find it challenging to be much innovative in this environment. Moreover, due to cut-throat competition, implementing changes in an application could be tough.

But if you wish for your application to grow, you must constantly keep adding new, advanced functionality and features that can fulfill the customer's demand. This is where APIs and Microservices architecture come into action.

But there is great confusion between these two, and they can never be sure which solution would be best for them.

This article aims to compare API vs Microservices and end all the confusion related to these solutions. We assure you that by the time we conclude this article, you will easily be able to decide which is the best method to develop and deploy your application.

First, let's understand what these terms mean:

What is an API?

An API or Application programming interface is the solution that helps in establishing communication between applications. If we have to speak in a more technical aspect, an API is a group of methods and protocols defining how two applications exchange and modify the data.

APIs are a crucial part of our modern digital infrastructure as they are responsible for establishing efficient and standardized communication between applications with different construction and function.

An API is a tool that connects the public with the software's core component, and external developers can reach their hands to a few parts of the application's backend without the requirement to understand the functionality of the app. This is what establishes an API as a programmer's interface.

Usage of API

If you use any software, whether you know it or not, you are using APIs. This is because API enables integration of the software- they enable software entities that are different to share functions and information.

Let's understand this by an example: Imagine you are shopping online and want to check out. You notice that the store you are shopping on provides you with the option to complete your payment through PayPal, a payment app, and since your account already exists on this app, you can complete your payment with one click. Convenient, isn't it?

Since PayPal is a different company from the online store you are shopping on, an API establishes communication between PayPal and the online store. First, the store utilizes PayPal's payment gateway API to request the user's required payment information. Next, PayPal's API discovers the request, validates it, grabs the information from PayPal's user database, and sends it back to the online shopping store. In the final step, the online shopping store uses your card information to make the payment and complete your transaction.

Thanks to PayPal, your favorite online store can access all the required information necessary to complete the checkout without needing to access PayPal's private data. Also allows you to complete the transaction on the same app without the requirement of navigating the transaction outside the application.

Exchange of information like the above application happens almost whenever two or more apps are required to work together simultaneously. Some of the other real-world examples include; A travel website that utilizes an airline's API to access prices and flight timings, embedded videos on YouTube, a website utilizing social media's API to allow social login, and different navigation apps that access a public transit system's API to capture real-time data of transportation.

REST APIs

Since an API is becoming more of a concept, programmers can build an API in whatever way they please. However, most programmers rely on Frameworks in order to create those APIs.

Representational State Transfer, or REST, is one framework that allows the development of APIs, and the API that is developed using the REST framework is called REST API. REST APIs are the most commonly used APIs for microservices and cross-platform integration.

You can assume REST as an outline or blueprint that could be used to develop APIs to make these APIs secure and efficient. REST APIs work on a model of Feilding HTTP requests and, in return, respond in JSON (JavaScript Object Notation). The standard protocol for proceeding with web-based data transfer is the Hypertext Transfer Protocol HTTP. So, if an individual has some knowledge of HTTP, he can easily learn the process of developing or interacting with a REST API.

External vs Internal APIs

The APIs we have discussed have been a specific type of API known as web API. These types of APIs establish communication between two or more web servers. Also, the example we discussed earlier are open APIs, i.e., these APIs are available to be used by anyone, including the developers of third-party software.

However, it is not necessary for APIs to be available publicly. Instead, APIs are used for establishing communication within the application, and the access is mostly restricted to the organization's authorized developers, and employees only are known as Internal APIs.

Now that we know about APIs, let's start discussing Microservices.

What is Microservice?

A microservice is a type of software architecture that divides the application's different functions into smaller parts called "services". When the application is developed in this manner, it is said that this application follows microservice architecture.

For instance, the microservice architecture for a payment application like PayPal could contain individual services for managing the user's account, incorporating online merchants, and authenticating users. Every service functions like its very own micro piece of software in a much larger system.

Every service that comes under the larger microservices has just a sole task, but it is up to the app's developer to decide the scope of these tasks. For example, a basic software application might rely on certain services, such as PayPal. Or, if we take an example of a big software company, an application might be required to compromise a vast number of granular services with highly particular functions.

Why should a developer use Microservice Architecture?

To understand the benefits of a Microservice Architecture for a software developer, we must first understand its ancestor, the monolith. A monolith application is totally the opposite of a microservice- instead of providing different tasks to various self-contained services, in a monolith, each and every function of the software application is controlled by a single program.

It might make sense to most of you to start the application development in this specific way- why should a developer create multiple programs to look after? However, the issues start to arise once the monolith faces problems handling the complexity and capability of constantly growing applications. For example, when the developers try to stuff every aspect of a particular application into a single program, release updates, discover problems, keep a record of changes, and generally try to understand the code, it becomes difficult for a single program to handle all these applications all by itself.

In simple words, everything is so closely connected in the monolith that it is no less than a challenge to untangle them. This was the reason why the need for a new type of architecture arose, and microservice came into existence. When we compare it to the monolith, the microservice architecture helps in improving:

Overall, by distributing responsibilities, microservices simplify and expedite the process of software development.

Obviously, a collection of individual modules won't be of much benefit for an application, which is why all these services are linked together with APIs.

Microservices vs API

Let's have a swift review before making the comparison:

• An API is a software solution that makes communication between two or more software applications possible. A software application's API defines a group of allowable requests to be made to the API and replies to these requests.

• A microservice is a framework for developing an application that breaks down the software application's work into modular, self-contained programs. Microservice simply allows the developers to develop and maintain software.

Although they are quite different, API and microservices are often paired together, as services contained in microservices often utilize APIs to communicate within themselves. Similar to how different applications use open public APIs to integrate with other applications, one aspect of a microservice utilizes a private API to access different parts of the same microservice.

Inside a microservice, every service has its own specific API responsible for determining what request it might receive and how it responds. The principle followed by these APIs is generally the REST principle.

It's important to understand that no two microservices are similar, and all use the API with different approaches. Some may assign multiple APIs to a single service or may utilize a single API to access multiple services.

One must also remember that APIs have usage beyond the microservices. For example, as we had already discussed, web API helps enable data-sharing between systems, which is crucial for many web applications. Also, APIs might be used internally but without any microservices implementation.

Similarities and differences

Now that we have discussed API vs Microservices and their uses, components, and benefits, it's time for their face-off.

Similarities

First, let's take a look at the similarities between the two:

• Both APIs and Microservice are used in the development of softwares to accelerate testing, development, and execution without compromising on quality.
• They both support cloud-based applications.
• APIs and Microservices offer the ability to develop applications, functions, and modules swiftly.
• Both can reduce software development costs by minimizing complexity, errors, and risks.
• As they both have a distributed nature, API and Microservices provide security. Even when a single service is compromised, other services won't be affected.

Differences

Microservices are the stepping stone of an application, but API is the glue that keeps all the components of microservice-based applications together. So let's compare microservices vs API on different bases.

• Microservice architecture is a model of software development which divides an application into micro parts of services. Whereas APIs are interfaces or intermediaries between two applications that require establishing a communication. It consists of features that help consumers to utilize an application's underlying services.
• The components of microservices could be compared to bricks that help build an application. On the other hand, APIs are "functional blocks" responsible for performing different tasks.
• The components of a microservice include APIs, a data access layer, business logic, and a database. At the same time, an API contains the format, protocol, functions and procedures, and tools.
• There are two types of microservices: Staefull microservices and stateless microservices. Meanwhile, APIs could be private, public, database, partner, remote, SOAP, REST, etc.

Conclusion

APIs and Microservices are utilized in software development; both offer an organization many benefits, such as flexibility, security, agility, and scalability, while producing high-quality software.

However, many individuals confuse the two as microservices services often use APIs as their communication tool. This is the reason why the battle of API vs Microservices started.

The architecture of Microservices is a software development model where the functions of an application are broken down into micro functions, each with its own data and dependencies. While APIs act as an intermediate that helps two applications in communicating.

It would be much more beneficial for an organization to use both of them together instead of comparing them. Working together can help increase the effectiveness of a microservice model while enhancing the application's security, scalability, compliance needs, and cost reduction.