REST expanded as a REpresentational State Transfer is an architectural style for distributed hypermedia systems. It was first presented by Roy Fielding in 2000 in his famous dissertation. Like any other architectural style, even REST does have it’s own 6 guiding constraints.

Guiding Principles of REST

These Guiding Principles of REST are which must be satisfied to refer to an interface as RESTful. They are listed below.

Client-server – By dividing the user interface concerns from the data storage concerns, we develop the portability of the user interface across varied platforms and gain scalability by interpreting the server components.

Stateless – Each request from a client to server must include all of the information required to concede the request, and cannot take benefit of any saved context on the server. The session state is hence kept completely on the client.

Cacheable – Cache constraints demand that the data within a response to a request be completely or explicitly labeled as cacheable or non-cacheable. If an acknowledgment is cacheable, then a client cache is given the right to reuse that response data for following, equivalent requests.

Uniform interface – To achieve a uniform interface, multiple architectural constraints are required to guide the behavior of components. REST is described by four interface constraints:

  • identification of resources
  • manipulation of resources
  • self-descriptive messages
  • hypermedia as the engine of application state.

Layered system – The layered system style provides an architecture to be comprised of hierarchical layers by constraining component behavior such that any component cannot “see” beyond the next layer with which they are interacting.

Code on demand (optional) – REST allows client functionality to be prolonged by downloading and executing code in the form of applets or scripts. This interprets clients by reducing the number of characteristics required to be pre-implemented.

Best Practices for Building RESTful APIs

From here are suggestions, guidance, and instructions to design RESTful APIs that make your users happy.

Don’t return plain text

Although it is not required by the REST architectural style, most RESTful APIs use JSON as a data format. However, it is not acceptable to return a body containing a JSON-formatted string. You need to stipulate the Content-Type header too! It must be fixed to the value application/JSON. This is particularly important for programmatic clients as some of them rely on this header to accurately decode the response.

Avoid using verbs in URIs

If you’ve conjectured the basics, you’ll now understand it is not RESTful to put verbs in the URI. This is because HTTP verbs should be adequate to describe the action being displayed on the resource.

Use plural resource nouns

It may be difficult to decide whether or not you should use a plural or singular mode for resource nouns. However, it is advised using the plural form. Why? Because it implements all types of endpoints very well.

Return error details in the response body

When an API server handles an error, it is useful (and advised!) to return error details in the JSON body to assist users with debugging. Special kudos if you add which fields were influenced by the error!

Pay attention to status codes

This one is super relevant. It is one thing you need to memorize from this article. The most dangerous thing your API could do is return an error response with a 200 OK status code. It’s really poor semantics. Instead, return a significant status code that accurately describes the type of error.

Use status codes consistently

Once you’ve learned status codes, you should strive to use them consistently. For example, if you choose that a POST endpoint returns a 201 Created someplace, use the equivalent status code for every POST endpoint. Why? Because users shouldn’t have to worry about which method on which endpoint will deliver which status code in which conditions. So be harmonious, and if you stray away from conventions, document it somewhere with big signs.

Handle trailing slashes easily

Whether or not URIs should have a trailing / is not really a discussion. Simply pick one way or the other i.e., with or without a trailing slash and stick to it. Make sure that you gracefully redirect clients if they use the wrong convention.

Make use of the query string for filtering and pagination

A lot of times, a simple endpoint is not enough to meet complicated business cases. Your users may want to reclaim items that fulfill a particular condition or retrieve them in small amounts at a time to enhance performance. This is precisely what filtering and pagination are performed. With filtering, users can define properties that the returned items should ought. Pagination allows users to reclaim fractions of a data set.

Learn the difference between 401 Unauthorized and 403 Forbidden

When handling security errors in an API, it’s very simple to be mixed about whether the error relates to authentication or authorization. Here’s a quick way for knowing that.

  • Has the user not given authentication credentials? Were they wrong? ? 401 Unauthorized.
  • Was the user perfectly authenticated, but they don’t have the wanted permissions to enter the resource? ? 403 Forbidden.

Make good use of 202 Accepted

I find 202 Accepted to be a very convenient alternative to 201 Created. It primarily means that the server has understood the request but have not created the resource (yet), but it is fine.

Use a web framework specialized in RESTful APIs

New frameworks have emerged in different languages that are uniquely made to build REST APIs. They help you follow the most excellent practices hassle-free without reducing productivity. It is strongly recommended that you give these frameworks a shot! They will help you build attractive, rich, and well-designed REST APIs.

  • In Python, one of the best API frameworks is Falcon. It’s just as simple to use as Flask, amazingly fast, and excellent for building RESTful APIs in minutes.
  • If you’re more of a Django type of person, the go-to is the Django REST Framework. It’s not as natural, but incredibly potent.
  • In NodeJS, Restify seems to be a good candidate.


Hopefully, this article helped you learn some suggestions and procedures to build more beneficial REST APIs. REST API design is a proficiency more than anything else. If you have a diversified approach to some of the details above, please comment. Skyhidev is the top mobile app development company in Toronto. Contact us to get your dream project.