Is API Frontend or Backend? Exploring Its Roles in 2023

Learn what an API is and whether it is a frontend or a backend component. Plus, discover some benefits of using APIs in web development.

APIs—also known as Application Programming Interfaces—are a set of protocols and rules that allow different software components to interact and exchange data. In modern web development, they are essential for accessing data and services from various sources such as databases, servers, cloud platforms, and third-party providers. 

However, what exactly is its role in web development? Is an API a frontend or a backend component? How does it interact with the different layers of a web application? This article will answer these questions and include examples of how APIs are used in front and backend development.

What Is the Difference Between Frontend and Backend Development?

Frontend development—also known as client-side development—involves creating the user interface of a web application. It is the part of a website or web application that users interact with and see. 

Frontend developers use HTML, CSS, and JavaScript code to create web pages that are visually appealing, functional, and interactive. The code runs in browsers and determines the web pages’ layout, design, and functionality.

Backend development, on the other hand, is the process of creating the logic and functionality of a web application. It occurs on the server side of the application. Therefore, it is not visible to users. 

Backend developers use server-side languages (like PHP, Python, Ruby, and Java) and databases (like MySQL, MongoDB, and PostgreSQL) to store and process data and provide the services and functionality that a frontend requests.

Is an API a Frontend or a Backend Component?

An API is frontend or backend, depending on its type and intended use. Different types of APIs—including REST, SOAP, and GraphQL—follow various standards and formats for exchanging data.

SOAP vs. REST vs. GraphQL

The most commonly used type in web development is the REST API, which stands for Representational State Transfer. REST APIs are web services that adhere to the REST architectural style and utilize HTTP methods like GET, POST, PUT, and DELETE to execute operations on resources like data, files, and images identified by URLs. Depending on whether it is employed to consume or provide data and services, a REST API can function as either a frontend or backend component.

Frontend APIs

An API is a frontend component if it is used to access data and services from backends or other sources. A frontend API can retrieve data from a database in a backend, authenticate a user, process payments, display maps, or play videos. These APIs can be custom-built or provided by third-party sources such as Google, Meta, and X.

Some examples of frontend APIs are:

• Google Maps API allows you to embed interactive maps and geolocation features into your web applications.
• YouTube API enables you to access and manipulate YouTube videos and playlists in your web applications.
• Stripe API lets you integrate online payment processing and billing features into your web applications.

Backend APIs

When it is part of backend development, an API is used to provide data and services from backends to frontends and other applications. For instance, custom-built backend APIs can be used to perform business logic and calculations, create, read, update, and delete data in a database, send emails and notifications, as well as generate reports and analytics. In addition, third-party API services from external providers such as Amazon, Microsoft, and IBM offer similar functionalities.

Some examples of backend APIs are:

• Amazon S3 API allows you to store and retrieve files and objects in the cloud.
• Microsoft Azure Cognitive Services API enables you to add artificial intelligence and machine learning features (such as face recognition, speech recognition, and natural language processing) to your web applications.
• SendGrid API lets you send and receive emails and notifications in your web applications.

Read more: Top 12 Back-End Technologies Recommended by Expert Devs

Examples of APIs Used in Frontends and Backends

To illustrate how an API is frontend or backend depending on its type and purpose, let us consider a simple example of a web application that allows users to search for and book hotels. It consists of the following components:

• A frontend that displays the user interface and enables users to enter their search criteria (such as location, date, and price) and view and select the available hotels
• A backend that processes users’ search requests, returns the matching hotels from a database, handles the booking requests, and confirms the reservations
• A third-party API that provides additional information (like ratings, reviews, photos, and maps) for hotels

In this case, the frontend communicates with the backend through APIs to ask for and receive the necessary data and services. To request a list of matching hotels in JSON format, the frontend APIs can use the HTTP GET method to send users’ search criteria to the backend. On the other hand, to confirm users’ booking details, the HTTP POST method can be utilized to receive the confirmation message in JSON format.

Meanwhile, the backend communicates with the database through APIs to perform the necessary operations. The backend APIs use SQL to retrieve data matching users’ search criteria and insert data corresponding to users’ booking details.

Moreover, third-party APIs can be employed to enhance the user experience and provide additional information and features. For instance, the TripAdvisor API can fetch and display the ratings, reviews, photos, and other relevant details of hotels. Users can also use it to filter and sort hotels based on these criteria. Additionally, the Google Maps API can show the location and distance of hotels on a map and provide direction and navigation features.

5 Benefits of Using APIs

Whether belonging to frontends or backends, APIs provide many benefits for developers, users, and businesses. Here are some of the main ones:

• Reusability: By utilizing APIs, you can repurpose pre-existing code and functionality instead of starting from scratch. This saves you time, effort, and resources and elevates the code’s overall quality and consistency.
• Modularity: APIs make breaking down a complex web application into smaller, more manageable parts possible. Each component has its own API, making it easier to comprehend, maintain, and test the application as a whole. This provides greater flexibility and scalability, enhancing the overall performance of the web application.
• Interoperability: APIs facilitate seamless communication and data exchange between software components, regardless of their programming languages, platforms, and architectures. This lets you seamlessly integrate and utilize data and services from various sources, including databases, servers, cloud platforms, and third-party providers.
• Security: By implementing authentication, authorization, encryption, and other security measures, APIs enable you to regulate and restrict access to the data and services you provide. This prevents unauthorized or malicious users from accessing and misusing your data and services, ensuring the privacy and integrity of your data.
• User Experience: APIs are essential in creating immersive and engaging user interfaces. They provide valuable data and services that significantly enhance the functionality and interactivity of web pages. By doing so, APIs help improve user experience and satisfaction, leading to higher user engagement and retention rates.

Conclusion: Is API Frontend or Backend?

APIs are rules and protocols that allow different software components to communicate and exchange data. They are essential for building modern web applications, as they enable developers to access and use data and services from various sources. 

An API is frontend or backend, depending on its type and purpose. A web application can use both frontend and backend APIs and third-party APIs to create a rich and interactive user interface and perform complex and dynamic functions.