Technology December 18, 2019 Last updated December 18th, 2019 2,015 Reads share

5 Things to Remember When Designing for REST API

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Being able to create a functional and reliable REST API (Application Programming Interface) is an essential skill for any developer. Not only is this particular skill in high demand, especially in today’s software development industry where online functionality is essential, but it also speaks well about a developer’s expertise when their own application has elegantly crafted REST APIs. As such, a coder who’s competent with REST API development will certainly have no shortage of employment or project opportunities.

With that said, designing good REST APIs can be quite challenging. Fortunately, we can look at the best practices that the general API coding community has discovered to contribute significantly in their REST API designing efforts. But before we get into more detail, let’s briefly have a recap about REST, and REST API.

What is REST, and what is a REST API?

REST stands for Representational State Transfer. It is a specific type of architectural design for APIs that is commonly used in the development of web-based software, apps, and web services. Thus, an API designed according to REST principles is called a REST API.

The main purpose of a REST API is to give a web-based application or web service the ability to interact with data stored in a web server. This interaction is done through the HTTP Protocol and usually involves any of the following main operations:

  • POST, which creates a file on the server
  • GET, which retrieves a file from the server
  • PUT, which updates the file stored on the server
  • DELETE, which removes the file from the server

A common example of a REST API at work is Twitter’s API. When a developer implements the Twitter API into their application, they empower that application to be able to utilize the information stored and displayed on Twitter’s servers. For example, if the application needs to show the entire history of tweets of a specific user, then the GET function of the Twitter API would be used to do just that.

Now that we’ve defined what REST is and what REST APIs are, here is the list of things you should remember when designing APIs.

Using an API designing tool can significantly reduce the amount of work you have to do.

Designing and coding an entirely new REST API from scratch can a lot of time and effort. As such, it’s recommended that you use a stable API design, planning & modeling tool to give yourself a helping hand. Using such a tool allows you to easily prototype and distribute your latest REST API to your team members, as well as automate the more tedious tasks related to API design, such as creating hosted documentation or creating mock servers for testing. These benefits can significantly decrease how much work you need to do, thus enabling you to handle more development-critical tasks. Some examples of these tools include Swagger, Postman, and others.

Avoid using verbs for URIs (Universal Resource Identifiers) and use nouns instead.

When it comes to REST API URIs, it’s best to just use nouns rather than insert verbs into them. This is because the verbs related to the HTTP methods are usually enough to describe what is being done on the resource. For example, instead of using “GET /fetchimages” for an endpoint action related to fetching specific images, you should use “GET /images”. There is no need to add “fetch”.

Be detailed when it comes to error messages.

It’s inevitable that a user interacting your REST API will make a mistake somewhere and trigger an error situation. In this situation, it’s ideal to give the user the information they need to figure out just what was wrong and how to resolve it. This can be done by crafting specific error messages that pop up when a corresponding error condition is triggered.

With that said, your error messages should be detailed. It shouldn’t just tell the user that they did something wrong somewhere; it has to be more informative than that and should point them towards the general direction of their mistake. A great example would have the following:

  • An HTTP status code. There are 71 distinct HTTP status codes used widely in software development today. Using one in your error handling will give the user a general idea of the nature of their error.
  • An internal code ID. This should be where your system of error code IDs comes into play if you’ve created one. If this is the case, then your API documentation should have a specific section where the meaning of all your code IDs is explained.
  • Human-readable message: A plain text message explaining the error in simple language. It may simply notify the user about its case, its context within the API, or even a possible solution.

Don’t neglect API testing.

Testing your REST API is key to ensuring its functionality. Moreover, it is also essential in rooting out dangerous security flaws, bugs, and other issues that may compromise your API as well as those who use it. As such, you should never neglect to subject your API to repeated and rigorous tests, even if it may take up time and resources, as the results are usually worth it at the end. Also, frequent API testing can help you in optimizing user experience, something that can have a significant effect on your REST API’s adoption rate.

Design your REST API for a singular purpose or problem.

Last but not least, you should take care to design your REST API in such a way that it should do one thing very well, or delivers a solution to a singular problem at the very least. Doing so will prevent your planned designs and prototypes from looking disorganized, muddled, or lacking in conviction. Moreover, it will give you a clear idea of what to build towards, which makes for a leaner and more focused REST API.


The ability to design a reliable and functional REST API is a skill that will prove to be highly valued in the software development industry for years to come. Even seasoned API development companies like Stoplight understand the value of good API design choices. Whether you’re a software developer who’s looking to brush up on REST API development or simply someone looking for new coding opportunities, then you should consider adopting the best practices listed above. Having them in your repertoire will prove to be greatly beneficial in your REST API creation efforts, as well as open multiple doors of opportunities for you.