How are REST APIs Designed?

One of the questions that many newbie developers ask is how to design a good REST-API? What they actually want to know is the common REST API design patterns. The answer to this question is simple, i.e., as long as you know the underlying principles of the HTTP protocol, it is only a matter of using good data modeling which is mainly based on a solid skill foundation. We outline and simplify the design process of a solid API.

REST and HTTP

The designing of a REST-API is something that is best suited for developers who have data modeling skills. It is very apparent that REST is based on using resources which follow a specific data model.

Almost everything on the internet communicates via the HTTP protocol. Your browser, for instance, sends HTTP requests to the web server and in return, the web server sends those responses back. If anything, HTTP is the predominant client-server protocol which allows clients to not just query but also manipulate server-based resources like:

  • Return a webpage which was requested via the URL
  • List all available or unavailable resources
  • Delete resources via the URL
  • Create resources and return its new URL

The resources mentioned above can be just about anything from content on a website to real objects like sensors of a nuclear reactor or perhaps data in an encrypted database or results from a complicated equation. When it comes to HTTP everything has a URL, and a set of commands usually ‘verbs’ are used to change, delete, create, and update each and this is what is referred to as ‘RESTful.’ The ‘R’ in the term actually stands for Resource!

Everything that has a connection to the internet can either be a server in a conversation and perhaps a client in the next. That’s why many people refer to the internet as having a p2p or peer-to-peer structure or a network. It is the REST-API which is the native interface or the network’s connector. It is by far the best way to expose resources or functionality to the internet.

REST-API Designing

Now for an enterprise to truly become digital or perhaps connected it should become a valid HTTP-server. The REST-API is the primary channel which is the same as everything else on the internet. The good news is that designing a really good REST-API is quite easy, and straightforward if you follow the after-mentioned patterns and guidelines.

  • The REST-API by its very definition works to expose server resources which can be accessed and manipulated by clients via the API which has to be modeled by a robust data model. The data model works as a metaphor via which clients can directly connect to the API. The model will have logical and also physical resources with their associations.
  • The next step to ensure is that every resource in the model has to be exposed to the world is mapped via the URL. The URL needs to reflect the relationships they have with each other.
  • The next step is to have the manipulations assigned to HTTP commands like DELETE, POST, GET, PUT to give entry.
  • The request formats need to be created that are valid for the required entries in the model.
  • Each URL needs to be protected by validations and authorizations.

Live Example

Take for instance an insurance company’s API which would expose its resources like policies, customers, claims, etc. A home API connected would expose resources like solar panels, burglar alarms, lights, temperature, etc. And a mathematical software will need to expose resources like inputs, algorithms, and calculations. However, each one will do so with a unique set of URLs.

Each URL will allow clients to create and manipulate resources using a series of required verbs as mentioned above.

Moving Forward with REST-APIs

The abovementioned explanation with the live example is a very simplified version of what a REST API does and how it is designed. The logical flow of commands and manipulation of resources is just the tip of the ice burg, but it is an essential tip when considering that even the most complex software will use this very same structure and flow.

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