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Everything you need to know about APIs in software architecture

APIs in software architecture

What are APIs and why are they important?

APIs, or Application Programming Interfaces, are programming interfaces that can be used to design communication between two or more software solutions. They are an interface between one or more programmes or components within an application, through which it is possible to exchange data.

APIs have a crucial role in modern software development, as they offer numerous advantages:

  • Reusability: well-designed APIs allow developers to effectively reuse software components, reducing work duplication and speeding up the development of new functionalities. 
  • Modularity: thanks to APIs, it is possible to divide a complex system into independent modules, simplifying maintenance, management, and updates of the single applications' parts.
  • Interoperability: APIs favour the interaction between heterogeneous systems, allowing them to communicate in a standardised way, facilitating integration between the various technologies and services. 
  • Scalability: APIs can contribute to an application's scalability to satisfy the increasing work requirements, guaranteeing that the whole app remains resilient and efficient. 

Given the numerous advantages and increasing dependencies of APIs in modern software architecture, API comprehension and their correct implementation are fundamental for both developers and companies.


API types

There are different types of APIs, each with its own advantages, limitations, and use cases.

  • Function-oriented API: communication takes place via functions and parameters. This is the most complex type of API.
  • File-oriented API: access to individual files or file functions via a call to the file system; the operating system must be included due to access rights.
  • Object-oriented API: more flexible than pure function API; use of so-called interface pointers.
  • Protocol-oriented API: independent of specific operating systems or hardware

What is a REST API?

Among the best-known APIs are REST and GraphQL. REST stands for Representational State Transfer. It is a special type of interface responsible for the exchange of data on distributed systems. It is particularly important for web applications. Here, it is often necessary to distribute tasks and data to several servers or request them from servers (HTTP request).

If you would like to learn more about this concept, we recommend you read our article "REST APIs and GraphQL APIs: a comparison".


The role of APIs in microservice architecture

Microservices architecture has gained popularity over the last few years and allows developers to create applications as a set of small, independently distributable services. APIs play a crucial role in this approach, acting as a communication point between distributed services that are the backbone of these modern application infrastructures. These components are like the dialogue lines that allow the different services to cooperate synergistically.

In the context of microservices, APIs perform the following key functions:

  • Interaction between microservices: thanks to APIs, services can exchange data and requests in a reliable and structured way, making it possible to realise complex work fluxes and the combination of data coming from different sources. This effective communication is fundamental to guaranteeing that the microservice application functions as the sole coherent system. 
  • Independence of services: every microservice is an autonomous entity with its own business logic and its own life cycle. APIs offer a standardised interface that allows the developing team to work on each isolated microservice, without having to coordinate every change with other teams. This favours more development agility and the chance to release new functionalities rapidly and efficiently. 
  • Continuous evolution of architecture: updates or service substitutions can be handled without interrupting the entire system, provided that APIs remain stable and compatible. This allows microservices architecture to remain flexible and adaptable to the changing needs of company and users. 

Selecting the right APIs and following best practices, organizations can effectively use microservices architecture to reach their software development objectives. Without them, the ecosystem management of distriuted services would be much more complex, if not impossible. 


How does the programming language behind an API work?

The programming language underlying an API is used to define the API functionalities and behaviour. APIs are essentially a set of instructions or "endppoint" that a developer can use to interact with the system. 

When a developer makes an API request, the API's server-side code receives the request, processes it and returns a response. The programming language of the API determines how the server-side code is written and how it processes the request. Regardless of the programming language used on the server side, APIs return data in a standard format typically JSON or XML. For example, a Java-based API might use the Java Servlet API to process HTTP requests and responses, while a Python-based API might use the Flask or Django web framework, but in either case the response will be presented in one of the standard formats.

In short, the programming language of an API defines the syntax, libraries and frameworks used to implement the functionality and behaviour of the API. The format of requests and responses, on the other hand, is based on the chosen data interchange standard.

Although the programming of some APIs seems very complex and comprehensive, APIs should be simple and easy to understand. This means that the design of an API must be well structured and reduced to a minimum of functions. Only in this way can easily manageable APIs be programmed and used as modern microservices by a multitude of other software components.

An API can basically be realised with any programming language. We, for example, use GO, Ruby, Python and Node for our most powerful APIs. The API usually contains functions for communicating with the server, visualising data and controlling actions.


Why deal with API programming?

There are different reasons for which it's worth participating in API programming, not just in your role as a software developer:

  1. Increased functionality: APIs allow access to functions and data from other systems, making it easier to add new functionality to the application without having to develop everything from scratch.
  2. Improved interoperability: APIs provide a standard way for different systems to communicate and collaborate, making integration with other platforms and services easier.
  3. Improved scalability: by breaking down a complex system into smaller, more manageable parts, APIs can facilitate the scalability of the application and the addition of new functionality as needed.
  4. Improved accessibility: APIs can make it easier for developers to access and use the service, increasing its adoption and use.
  5. Improved security: by using appropriate security measures, you can effectively protect data and services when you provide them through an API.



In conclusion, APIs represent a vital element in the sphere of modern software architecture and play a crucial role in fostering communication and cooperation between different software components, services, and applications. In the first section, we've explored what's an API and why it is of such importance. APIs act as bridges between applications, allowing them to exchange data and functionalities in a standardised and efficient way, and this interoperability is fundamental for the success of modern applications.

We have also examined the various types of APIs and understood how each of them has its peculiarities and specific uses. In the context of microservices architecture, we've noticed how APIs are the binder that allows distributed services to communicate with each other, guaranteeing scalability, independence, and ease of maintenance. After seeing that APIs can be created with any programming language, we finally focused on the importance of understanding and managing API development, from the point of view that applies to both a developer and a company.

In a time in which integration, efficiency, and flexibility are essential for the success of applications, the knowledge of APIs and their correct implementation has become a competitive advantage. DevInterface offers advanced solutions in the development of APIs and integrations, offering the right skills and experience to support companies in the implementation and optimisation of their API strategy, contributing to strengthening their digital presence and reaching their maximum potential in the world of online applications and services. Contact us to receive a free consultation.