What are APIs and REST APIs?

Published: 30 April 2022


What is an API?

API is an acronym for Application Programming Interface. APIs are communication objects that receive requests and respond to them, using existing data and facilitating the search for data within platforms. APIs make it possible for different platforms to share information. Most modern applications offer APIs that give users and machines permission to integrate with their products.

Examples of APIs

APIs are present in most applications we use in our daily lives. Applications such as Facebook and WhatsApp are good examples of the utilisation of APIs. On Facebook, for example, we have an integration with Instagram, which allows photos and videos posted on the app to be automatically shared on Facebook as well. While in WhatsApp, we can see an integration of the contacts' list saved on the device with the app's contacts. These integrations are driven by APIs.

We can also see the use of APIs when making online purchases. For example, the platform used for payments needs to be integrated with the credit card operators systems. These are some examples of the most common APIs, which we can see in our daily lives, facilitating communication between platforms.

What are the advantages of using an API?

The benefits of using APIs are:

  • Security: APIs are secure, as they create a kind of barrier that does not allow full access to the system but only to the specific information that is part of that application.
  • Less data volume: Since each API is specific to a particular function, only the data that is required for the expected action is entered into the system.
  • Increases the efficiency of systems and applications: APIs support the improvement of systems' performance without having to start development processes that lead to this result from scratch.

What is a REST API?

In the world of programming, the concept of REST applies to the construction of Web Applications, such as software and websites, consisting of a protocol on the Information Architecture. In other words, software architecture aims for programmers to use some rules for a well-organised code hierarchy.

REST, is an acronym for Representational State Transfer, which is a set of restrictions used so that HTTP requests meet the guidelines defined in the architecture.

Essentially, the restrictions determined by the REST architecture are:

  • Client-server: the existing applications on the server and on the client must be separated;
  • Stateless: requests are made independently; thus, each one performs only a specific action;
  • Cache: the API shall use cache to prevent recurring calls to the server;
  • Uniform interface: groups four other concepts that determines that the resources must be identified, the management of the resources must be through representation, with self-describing messages and using links to navigate through the application.

Therefore, Rest API basically means using an API to access back-end applications, assuring that this communication is done with the standards defined by the Rest architecture style.

What is the REST API for?

When talking about “Rest API”, we talk about an API that follows the standards defined by the Rest architectural style. As previously stated, REST is a set of software architecture standards.

HTTP (HyperText Transfer Protocol) is the most popular way of transferring data. As for operations, it allows to:

  • Create data on the server (POST);
  • Update (PUT);
  • Search (GET);
  • Remove (DELETE).

Another possibility is HTTPS, an extension of HTTP, used to ensure security in data transport and is the most widely used on the internet.

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