How to Build a REST API:
Types and Requirements

Building a REST API? There’s a few things you’ll need to know before you get started. In this article, we break down the basics of REST APIs and tell you how they’re delivered, and what you need to do to create one. 

What Is a REST API?

A REST (representational state transfer), or RESTful, API is an application programming interface (API) with one specific feature: it adheres to the requirements of the REST architecture. This means it can interact with RESTful web services. REST APIs are used by household name companies such as Google, LinkedIn, Twitter, and Amazon. 

APIs, in general, operate in two directions: there is a call from the consumer of data (requesting a particular set of data, for example), and a response from the provider of data (providing a particular set of data, for example). In the context of restaurant locations and reviews, for example, the consumer would enter a zip code and in return the provider would send a list of restaurants in the area specified, along with reviews corresponding to that restaurant from the database.

One particularly interesting characteristic of a REST API call is that information contained in the header is vital. Identifiers, such as the requester’s metadata, cookies, caching information, and authorization data, are contained in each header, and that information is unique and relevant only to the call. 

Per the call data, one can obtain DELETE, GET, POST, and PUT data types, which enables deleting, reading, creating, and updating of resources respectively.

How Are RESTful APIs Delivered?

When a RESTful API is called, the information/representation can be made in several ways. It can be delivered by HTTP either as HTML, JSON, Python, XLT, PHP, or even plain text, but typically, JSON and XML are preferred (JSON especially because of its popularity and language agnosticism). JSON is also popular because it can be read by machines as well as humans.

How Do You Create a Rest API?

In creating a REST API, the first thing you need to consider are the criteria for the creation of such an API. As mentioned, REST APIs are unique in many ways, so you need to ensure that you are checking off each point as you engineer your interface:

• REST APIs have a client-server, managed through HTTP, that is made up of resources, servers, and clients. 
• Client-server communication is stateless, in so far as there is no storage of client information between each GET request (i.e. every GET request is free from connection with any other).
• Data is cacheable.
• Resources are identifiable from representations made to the client.
• Client messages have sufficient data and instructions to be processed by clients.
• Clients should be able to use hyperlinks to access all other actions they may take.
• Security, load balancing, and other types of services should be layered in the system with zero visibility to clients.

Although demanding in some respects, these requirements are fewer and less complex than those of protocols like Simple Object Access Protocol (SOAP), which demand XML messaging and inherent security compliance (resulting in heavy infrastructure). REST acts more like advice or principles, which make it way more suited to development applications like mobile and Internet of Things (IoT).

As for building your REST API, your exact approach will depend on what gateway you’re using, but typically you must:

• Choose a data format (direct, feed, or database) depending on your project needs.
• Communicate your API’s resource model through your URI.
• Specify your endpoints.
• Backup your old API versions and keep them running (if users need them).
• Establish robust security protocols (e.g. use HTTPS, restrict HTTP methods, use OAuth, and so on).
• Develop means for error handling.
• Create documentation so users know exactly how to use your API, decreasing their time and resource expenditure.

What Are the Different Types of APIs?

REST APIs are just one type of API, and others to be considered are SOAPs (as mentioned) and RPCs, which stands for Remote Procedural Calls. 

SOAP APIs

A Simple Object Access Protocol (SOAP) is a web API, emerging in the 1990s. Rules around SOAP APIs are strict and this renders the API complex in practice (which makes them resource-intensive and costly). This is one reason SOAP APIs fall victim to the preference for the much more lightweight REST APIs.

RPC APIs

A Remote Procedure Call (RPC) API was among the first invented, as well as now being the simplest type of API. All RPC APIs enable the usage of code on a given server. In simple terms, RPC APIs allow developers to make apps that can link together several services.

RPC APIs are split into two groups: XML-RPC APIs, and JSON-RPC APIs. XML-RPC APIs of course require formatting in XML but they execute simple HTTP server requests. They are easy to develop but are coupled (meaning one change could affect another). JSON-RPC APIs are also easy to develop and also coupled, which means they have the same levels of restrictions as XML-RPC APIs. The only real difference is that JSON-RPC APIs are, as the name indicates, coded in JSON, which is generally more accessible.

How Integrate.io Can Help

If you are considering building a REST API, Integrate.io can help. Our API allows you to control and monitor clusters and jobs whilst processing package data on the Integrate.io web app. If you need oversight of your project with the narrower management tasks of creation, monitoring, and termination of jobs built in, we could be a great fit for you. Click here to find out more.