API – A Standard for Integrating Multiple Applications

The API is an acronym for Application Programming Interface, which is being used for online transactions.

Author: Ana Nives Radovic
Publication: Fintechlopedia 2021
Presented in association with Visa Inc.

An API is a vital IT solution that facilitates communication and exchange of services or data between different applications. The evolution of the web has led to the growth of websites that enable individuals to trade and businesses to sell their products online. An API is a standardized set of functions, classes, methods, and constants that acts as a facade allowing software to offer its services to other software.

APIs are provided by software libraries or web services, and come with a description that outlines how consumer programs can make use of the software vendor’s program functionality. The primary function of an API is to establish a standard for collaboration between IT programs or services to promote reuse.

APIs enable software to interact with each other without human intervention, which is essential in a world where multiple applications are used simultaneously. APIs have revolutionized software development by providing developers with the building blocks to create complex applications without starting from scratch every time. By utilizing existing APIs, developers can save time and resources, while ensuring that their software is up-to-date and secure.

APIs are the backbone of the modern web and have become an integral part of our daily lives. From social media platforms to e-commerce websites, APIs are used to enable interactions between different applications, making our lives easier and more efficient.


The integration of APIs has become a crucial aspect of modern business applications. It enables businesses to streamline their operations, improve their productivity, and create new applications and services. By leveraging the power of APIs, businesses can stay ahead of the competition in today’s fast-paced digital world.

In today’s digital age, businesses rely heavily on technology to streamline their operations and improve their productivity. As the number of applications used by businesses continues to grow, it has become increasingly important to integrate these applications for better efficiency and seamless workflows. This is where Application Programming Interfaces (APIs) play a vital role.

APIs allow businesses to present a catalog of functionalities that come from various applications, databases, or file systems, both on the internet and on the local network of the company. The API acts as a mediator between different applications and enables them to communicate with each other, providing a seamless integration experience.

The use of APIs has become a standard technology for the integration of several business applications, as web and software players use it more to provide programmatic access to offers. Rather than just using traditional graphical interfaces, APIs offer a more efficient and streamlined way for applications to communicate with each other.

For example, when you use an application on your mobile phone, the application connects to the internet and sends the data to the server. The server then downloads this data, interprets it, performs the necessary actions, and sends the data back to your phone. The application then interprets this data and presents the requested information in a readable mode. The API allows the entire process to take place in a unique way as all data passes through it.

APIs generally offer a set of functions that enable queries and access to application services through a programming language. This means that developers can easily integrate different applications and systems by utilizing APIs, saving them time and resources. Additionally, APIs help businesses to create new applications and services by combining the functionalities of different applications, resulting in improved productivity and efficiency.


The primary purpose of Application Programming Interfaces (APIs) is to enable third-party systems to access functions and content from different software programs. Essentially, APIs allow for the interaction of several software programs, enabling them to communicate with each other.

To understand how APIs work, we can compare them to the telephone directory dialing service. Just as the dialing service allowed us to obtain the number of another contact, the API acts as a directory that enables a computer to request information from another computer over the internet.

In order to enhance the provision of services in this area, it is essential to integrate and connect the offer with various software programs that enable mutual communication. APIs are an effective tool for achieving this, providing maximum flexibility, simplicity, and controllability, in a more straightforward way compared to any other method.

APIs provide the ability to remotely access application functions or data, usually from another application, via a standard interface. This request is sent to the target software in a universal language that the API language represents, like a type of universal Esperanto. The requested software can then understand what is required and perform the necessary actions, delivering the required content.

APIs play a vital role in modern software development by simplifying the communication process between different applications, databases, or file systems. They provide a standardized way for software programs to interact with each other, regardless of the programming language, operating system, or platform used.

The use of APIs can result in significant benefits for businesses, such as increased efficiency, improved productivity, and reduced development costs. With APIs, businesses can integrate different software systems, create new applications and services, and offer better customer experiences.


APIs can be divided into three broad categories: open API, internal or private API, and partner API.

An open API, also known as a public API, is an API that is publicly available without any restrictions. It allows developers to programmatically access a proprietary software application and create new applications and services based on its functionalities. Open APIs are typically published for third-party development as part of the SDK (software development kit) or as an open API published on the internet.

Internal or private APIs are designed by companies according to their specific needs. These APIs are not available to the general public, and they are typically used to enable communication between different applications and systems within the company. Internal APIs are used to streamline the workflow and improve efficiency by providing access to the functionalities of different applications.

Partner APIs are available through a license or special access right. They are typically used by companies to enable communication between their application and those of their partners or affiliates. Partner APIs are used to share data and functionalities between different applications, enabling seamless integration between them.

On the developers’ side, APIs define how to write a program that requires services from the operating system or other application. APIs are implemented by function calls that consist of verbs and nouns, with the required syntax described in the documentation of the application being called. If the applications are written in different languages or for different platforms, the communication between the two applications is enabled by middleware that provides messaging services.

Understanding the different categories of APIs is essential for software developers to create applications and services that are integrated with different systems and platforms. Open, internal, and partner APIs all have unique functionalities and are used for different purposes. By utilizing APIs, developers can improve efficiency, streamline workflow, and create new applications and services that are tailored to their specific needs.

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This content was brought to you by VISA, the global leader in digital payments, whose mission is to connect the world with an innovative and secure payment network to enable individuals, businesses, and economies to grow.

Visa is the general partner of the Fintechlopedia project, an electronic glossary containing all relevant elements of digital transactions and related phenomena, situations, processes, and innovations.


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