Almost everyone today provides an API in this day of age. Some of the most popular APIs making their rounds across the internet is Twitter, Facebook, Stripe, Github, etc. If you want to build a web API design or perhaps want to provide access to a mobile app being developed or perhaps want to add some external data to a website it has to be easy to implement. But most of all it has to be a useful API that developers find worth the effort.
What is a Web API?
It is a question that most people who are developers already know the answer to it but those who are just starting out still aren’t clear about. An API is just an acronym for a fancy term ‘Application Programming Interface.’ It is a term that describes how programs and websites need to exchange data in a way that can be easily understood by computers. In contrast regular websites may exchange data in a form that is easily readable by a human being. For instance, websites might use CSS and HTML, but an API will be programmed using XML or JSON.
What is a RESTful Design?
The RESTful design also referred to as a paradigm is a list of rules which ensures that the API is predictable which in turn makes it easy for developers to understand. It is also the paradigm of choice for those developing web APIs.
Some important RESTful API design rules include:
- Incorporating a stateless design: What this means is that data is never stored in a single session. Which in other words means that every request will include information that is required by the client and server.
- Self-descriptive messaging: Generally, the idea here is to be able to understand all the responses and requests with spending the least amount of time in the way of reading the accompanying documentation.
- Semantics: It is imperative for the API to use all the existing features of the widely used HTTP protocol in a bid to improve semantics of the output and input. An instance of these semantics is using HTTP Status, HTTP Verbs, and authentication.
How Simple Should You Make it?
That is a tough question to answer but happens to be a very important one too. Ideally, you’ll want to design an API that’s easy to use and can be tested in a browser for the most part and yet it can still adhere to all the design guidelines. Though in reality depending on the type of API being developed compromises have to be made both in design and functionality which can add a bit of complexity to the project.
Structure the URLs
The structure of the URL happens to be the most important part of assembling a web API. It requires spending time to define the correct endpoint names which makes the API easier to comprehend by a developer and make it predictable. All URLs need to be descriptive and short which then utilizes the natural hierarchy of each path structure. Plus, consistency is equally important when using pluralization.
One way to keep things simple is when working with objects give it a unique ID within the URL while leaving everything for the string query to handle. If you are allowing the editing of objects, then the HTTP verbs are useful. All you have to do is apply them to the existing URL, and you’ll have a CRUD operation up and running.
While there is a lot more to developing RESTful APIs, the above is a good place to start. Moving forward newbie developers will want to study open source APIs to find out how it is structured.