API interface: basics for web developers

Programming  27. October 2023 Ján Májek

For modern web developers, API interface (Application Programming Interfaces) is an essential skill that opens the door to endless possibilities in the field of web development. The API allows applications to communicate and share data with other applications and systems, what is crucial for integration, automation and extension of the functionality of web projects. In this article, we will look at the basics that a web developer should know about APIs and we will show you some concrete examples.

What is API interface?

API interface is a set of definitions and protocols that determine how applications can communicate with each other. It is a mean that allows one piece of software (often reffered to as a client) to request certain functionality or data from another piece of software (often referred to as a server) through well-defined rules.

API interface types

There are different types of APIs, but the two most common are:

1. Rest (Representational State Transfer) API:

REST is an architectural style often used in web development. The RESTful API uses standard HTTP methods such as GET, POST, PUT and DELETE to manipulate data. Data is usually transferred in JSON or XML format. Example: When developing a social network, the REST API would allow the client to get a user’s friends list via the HTTP GET method.

2. SOAP (Simple Object Access Protocol) API:

SOAP is a remote procedure call protocol used for communication between applications regardless of programming language. SOAP API is more formal and structured compared to REST API and is often used in enterprise environment. Example: A bank could use SOAP API to perform remote transactions between its internal systems.

HTTP and API interface

HTTP (Hypertext Transfer Protocol) is the basic protocol for communication on the Internet and is often used when working with API interfaces. The following HTTP methods are common when using the REST API:


  • GET: Used to retrieve data from server. For example, getting a list of articles from a blog.
  • POST: Used to create a new data on the server. For example, creating a new user.
  • PUT: Used to update existing data on the server. For example, updating user data.
  • DELETE: Used to delete data from the server. For example, removing an article from a blog.

HTTP methods enable simple and standardized communication between the client (web application) and the server (API).

API interface


Authentication and security are important aspects when working with APIs. Authentication ensures that only auhorized users or applications can access the API. Various authentication methods include the use of API keys, tokens or login data. Authentication is necessary to prevent unathorized access to sensitive data or functionality.

Security ensured that the data transmitted between the client and the server is protected from unathorized access or attacks. Using the HTTPS protocol for data encryption and implementing security layers such as data authentication is necessary to ensure the integrity and credibility of transmitted data. Security measures, such as restricting access to certain parts of the API through permissions and roles, also help protect sensitive information. Developers need to be familiar with the latest security standards and practices when working with APIs to protect their applications and customers.

API Interface: Documentation

API documentation is a key element for its proper use. Precise documentation provides web developers with information on how to use the API, what data is available, what authentication rules are there and how communication with the API works. Well-accessible documentation makes working with the API easier and reduces the likelihood of errors.

API Interface: Examples of use

Let’s look at some concrete examples of using APIs in web development:

1. Social media integration:

A web developer can use a social media API, such as Facebook API or Twitter API to display live posts or to share a content on social media directly from a website or app.

2. Online payments:

When creating e-commerce sites, APIs of payment gateways are used to process online payments. This API allows clients to perform transaction securely.

3. Map services

Using map APIs such as the Google Maps API allows developers to integrate interactive maps into their websites, providing users with valuable geographic information.

4. Content Management

The content management API (CMS API) allows web developers to update website content from external applications or share content between multiple websites.

5. Email communication

To receive and send emails, web developers can use the API of email provides, such as the Gmail API or the SendGrid API.


API is a key skill for web developers and it is an integral part of modern web development. With its help, developers can integrate various services into their websites and applications, share data with other systems and create complex online solutions.

Controlling APIs opens the door to endless possibilities and gives web developers the ability to create connections between different applications and systems, increasing the functionality and value of their projects. It si important to constantly learn and keep up with the latest API trends, as this skill is increasingly important in the dynamic world of web development.

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Ján Májek

Ján Májek

Founder of UPVISION Digital agency


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