This article offers a general overview of REST APIs, their benefits and guiding principles. It will also help you decide whether Representation State Transfer is a good choice for your cloud environment.
Today’s enterprises operate in a highly competitive and dynamic environment where the smart use of data dictates successful delivery, fast speed to market and effective cost management. Netflix, Uber and Starbucks have built agile business processes with APIs that enabled them to increase the points of presence of their products and services across the globe. In addition, APIs have the potential to promote innovation and improve collaboration and customer service at any organization.
What Makes an Application Programming Interface (API) Great?
An API provides a list of operations along with the documentation that helps developers access web-based applications, standardize software operations and understand how systems communicate with each other. API simplifies programming by abstracting the underlying infrastructure and exposing individual objects you need to iterate new features or perform critical tasks.
A great API will encourage developers to use it and share it with others so they can create a transferable and centralized knowledgebase of best practices, well-organized code and reusable components for fast and efficient programming.
Let’s dig in by looking at the REST API as an example of the most logical and efficient standard API.
What is REST API?
REST or Restful API Design (Representational State Transfer) takes advantage of existing communication protocols and standard operations and aims to increase the speed of performance and reliability by reusing components that don’t affect the entire system, while the system is running.
REST is an interface between systems that use HTTP and/or HTTPS to obtain data and generate operations in all possible formats. It's flexibility allows developers to build an API that is not restricted by XML, JSON or any other format. It can be used on any protocol without the need for creating additional libraries or building supporting software. Additionally, users aren’t required to know procedures or specific parameters to operate REST.
Since REST separates the user interface from data storage concerns, it offers a portable and scalable way to create applications inside the client-server environment. And just like any other architecture, REST comes with its own guiding principles:
Stateless Client/Server Protocol
REST architecture is stateless, meaning that the server doesn’t store any record about the client’s session and each request from the client to server must carry all the information necessary to understand a request and perform an action. As a result, the server never relies on stored data or session-related dependency and, therefore, can handle any request in a timely and scalable fashion.
The stateless nature allows REST not only to scale your APIs to millions of users by deploying it to multiple servers, but it also reduces complexities associated with server-side state synchronization logic. Your servers will never lose track of where each client is in the application because every request carries its own information.
The goal of caching is to avoid generating the same response twice, which in turn, allows systems to gain speed and reduce server load. REST API’s cache constraints require data to be explicitly labeled as cacheable or non-cacheable. A cacheable response gives the right to reuse response data in equivalent requests while non-cacheable restricts clients from doing so.
Implementing caching is not an easy task because not every request is cacheable and takes time to configure. But at the end of the day, caching can significantly boost service performance and improve speed and consistency of your operations.
Since RESTful services require using a uniform and predefined set of stateless constraints to guide the behavior of each component, they significantly simplify the architecture by enabling every part to evolve independently while providing visibility into improved interactions.
REST is defined by four main constraints that constitute a uniform interface and help achieve system agility and scalability through stateless communication. They are resource identification; manipulation of resources through representations; self-descriptive messages; hypermedia as the engine of application state.
Finally, REST APIs can improve system scalability and enforce security policies by separating a client from the server. A layered system is built on client-server constraint and requires each layer to act independently and interact only with the layers that are immediately adjacent to it.
For example, you can deploy the APIs on one server, store data on another and authenticate requests on a completely different server. This minimizes the risk of coupling functionality in your service and allows for a lean and predictable request execution.
REST APIs build services that help solve organizational problems at hand. They provide valuable guidelines to developers and architects who decide how and where to use APIs they create and which rules to follow to meet specific goals.
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