A Comprehensive Guide to RESTful APIs

What is RESTful API?

REST, short for Representational State Transfer, is an architectural style used to design networked applications. RESTful APIs are a fundamental part of modern web development that enables easy communication between different systems over the internet.

Understanding REST

REST was introduced in 2000 and it provides a structured way for systems to interact by transferring data over a network. Unlike other approaches, REST focuses on stateless interactions, meaning each request from a client to a server must contain all the necessary information.

One of REST’s key advantages is its simplicity and scalability. Clients (such as web browsers) and servers can interact without prior knowledge of the other ones' server and the resources it hosts.

REST follows a resource-oriented design, where each piece of data (e.g., users, products, or tweets) is treated as a resource with a unique URL.

REST vs. SOAP

In contrast to REST, SOAP (Simple Object Access Protocol), is another protocol used for web communication and exchange of data over a network in various web services in XML format.

SOAP was developed as an intermediate language so that applications built on various programming languages could talk easily to each other and avoid the extreme development effort. Unlike SOAP-based Web services, there is no “official” standard for RESTful Web APIs. This is because REST is an architectural style, while SOAP is a protocol. REST is not a standard in itself, but RESTful implementations make use of standards, such as HTTP, URI, JSON, and XML.

The REST architecture has a number of features, most notably:

• The stability and uniformity of this architecture in place of the API
• Lack of session on the server-side. 
• Use of HTTP status codes
• Use URLs to specify paths
• Apply queries to URL instead of the HTTP header

Because of these features, web developers tend to use RESTful APIs to facilitate the web development process, better user experience, ease of use of IPs and data transfer through the HTTP protocol.

In addition, REST is more than a protocol; it’s a set of guides, principles, and rules that we can use to communicate between different sources.

Let’s take an example to better understand this.

Suppose we want to display the most popular tweets on our Twitter page. In such a situation, without having access to the server of Twitter, we will not be able to get this data. Usually, the services provide APIs for developers, providing them with the JSON format, but there are some services that use the XML format instead.

RESTful APIs operate over HTTP, the protocol that powers the web. To understand REST better, let's first look at HTTP.

What is HTTP?

HTTP (Hypertext Transfer Protocol) is the foundation of web communication. It governs how data is requested and transmitted between clients (e.g., browsers) and servers. Each HTTP request consists of:

• Headers – Metadata such as encoding, content type, and authentication details.
• Body – The actual data sent (e.g., form submissions or JSON payloads).

You can inspect HTTP requests in Google Chrome’s Developer Tools (Ctrl + Shift + J) or use tools like cURL, a command-line tool for making HTTP requests.

HTTP Methods (Verbs)

RESTful APIs rely on HTTP methods to perform operations on resources. The HTTP methods tell the server what to do with the data that you send via URL to the server. The primary or most-commonly-used HTTP verbs (or methods, as they are properly called) are POST, GET, PUT, PATCH, and DELETE.

These correspond to create, read, update, and delete (or CRUD) operations, respectively.

• Get: The get method requests a representation of the specified resource
• Head: The head method asks for a response identical to that of a GET request, but without the response body.
• Post: The post method is used to submit an entity to the specified resource, often causing a change in state or side effects on the server.
• Delete: The delete method deletes the specified resource.
• Patch: The patch method is used to apply partial modifications to a resource.
• Put: The put method replaces all current representations of the target resource with the request payload.

Most web pages that provide free information for developers typically allow access to specific data using only the GET method. The GET method is considered safe because it does not modify the resource—it only retrieves data (read-only semantics).

In addition to GET, methods like PUT and DELETE are idempotent, meaning that applying them multiple times results in the same state change as applying them once, even if the response varies. The GET and POST methods are cacheable, meaning their responses can be stored for future use. Some web applications permit developers to use PUT and DELETE, but they often require prior registration with the service provider.

Among HTTP methods, GET is the simplest and most widely used. For example, when you click on a link in Doprax, a GET request is sent to the server via the HTTP header, instructing it to return information about the requested resource.

As previously mentioned, the HTTP protocol consists of two parts: the header and the body. The header contains metadata in plain text or a structured format, while the body can hold various types of data, including text, images, HTML, XML, and JSON. When a browser sends a request to a server, the server processes it and responds accordingly, provided everything is correctly structured.

A common misconception is that REST and HTTP are inseparable. While the web primarily operates on HTTP, REST itself is not dependent on it. RESTful APIs can technically use other transport protocols like SNMP or SMTP, though in practice, almost all RESTful APIs use HTTP due to its widespread infrastructure, server support, and client libraries.

If you need assistance integrating your application with APIs on Doprax, our support team is happy to help. Feel free to reach out or contact our support.