Despite REST API – a simple, lightweight, and universal application programming interface – has been with us since the year 2000, REST API best practices slightly change over time. It’s totally understandable taking into account that it is about exchanging information and creating resources-oriented services, and the pace at which information technology alters, grows, and develops is truly mind-blowing.
However, REST API is certainly still proper for designing networked applications in the year 2021. To this day, it is used for communication between the server and the client’s software via the Web, and within this process, the existing protocols are being used. The software industry commonly accepts and utilizes REST API development guidelines at a wide scale, and thanks to them, stateless, reliable web services are designed.
In this article, we’ll discuss the following issues:
1. REST API and its standards in a nutshell
2. 9 REST API best practices in 2021
3. REST API standards – why they are still worth implementing
REST API and its standards in a nutshell
REST (an abbreviation that stands for Representational State Transfer) is a resource-based hybrid software architectural style for building APIs. It is made for distributed hypermedia systems and offers a set of guidelines to be implemented when designing and developing the architecture for the Web. It defines both resources and the way of accessing them, while, on the other hand, API (Application Programming Interface) enables access to resources. Interestingly, a resource may be any piece of information that can be named.
REST API both tell us about a set of good practices when exchanging messages between applications. What’s crucial here, is that to be called RESTful, a web service has to conform to REST constraints or REST API guidelines. This set of practices was formulated by Roy Thomas Fielding, the REST architectural style originator, in his doctoral dissertation in 2000. The list of REST API standards covers a set of interaction constraints proper to retain the software engineering principles guiding REST.
These constraints include:
1. Client-Server – By „separating the user interface concerns from the data storage concerns”, we get the improved portability of the user interface and better scalability.
2. Stateless – Concerns communication within the client-server interaction that is to be „stateless in nature, as in the client-stateless-server (CSS) style”.
3. Cache – Adding this constraint reduces the average latency of a series of interactions, and thus it is utilized to improve network efficiency, scalability, and user-perceived performance.
4. Uniform Interface – Simplifying the overall system architecture and improving the visibility of interactions may be obtained thanks to applying the software engineering principle of generality to the component interface.
5. Layered System – By adding layered system constraints and allowing system architecture to be composed of hierarchical layers, „we place a bound on the overall system complexity and promote substrate independence” which may be used for simplifying components and protecting new services from legacy clients.
6. Code-on-Demand – Downloading and executing code (as applets or scripts) may extend client functionality and, as a result, the number of features required to be pre-implemented goes down.
When fully conforming to RESTful API best practices, REST API should look like hypertext (or hypermedia).
9 REST API best practices in 2021
1. Using nouns instead of verbs
Resources you’re working with should appear as nouns that complement the verb standing for the HTTP request method in question, like GET, POST, PUT, and DELETE. Because the verb is already there, adding another one would only make things more complicated and ambiguous at the same time.
2. Keeping security in mind
Security issues have become crucial since REST API’s introduction. Using secure channels for communication as well as SSL/TLS and enforcing the principle of least privilege are all means to enable users to only obtain the information they are eligible to access.
3. Using plural resource nouns
This REST best practice is one of the most commonly mentioned. Using plurals for resource nouns is proper for all kinds of endpoints, and helps prevent ambiguity. But only if singular nouns are not mixed with plural ones, and the latter is the only form in use.
4. Making operations asynchronous
It is the answer to time-consuming request processing and problems with latency when waiting for completion before sending a response to the client. Utilizing HTTP status code 202 (Accepted) to inform the client about the current status might also help.
5. Using HTTP status codes for handling errors
Among dozens of status codes within the HTTP standard, there are at least several that should be in use to describe the erroneous return values. Some of them include 400 (Bad Request), 404 (Not Found), and 500 (Internal Server Error). It’s good to mention, however, that REST is not synonymous with HTTP, although many people may think so and tend to use this comparison.
6. Mastering HTTP status codes
Distinguishing the differences between codes such as 200 (OK), 201 (Created), and 202 (Accepted) may be difficult but is crucial not to mislead others. And the same goes for 401 (Unauthorized), used in the case of invalid authentication credentials, and 403 (Forbidden) when access is denied due to lack of required permissions.
7. Utilizing JSON
It’s good to use JSON, the lightweight data transferring standard, for both sending and receiving data. Apart from utilizing JSON for API output, it may also be considered for API input. A JSON-formatted string in the body is just the beginning, and the header needs to be properly specified, too.
8. Implementing versioning
In the world of fragmented information and constant changes, versioning may be what you need for your REST API. It’s proper, for instance, when you want to be up-to-date with the newest findings regarding recent modifications and improvements but don’t want to break clients.
9. Using frameworks that are proper for REST APIs
Some of the web frameworks for Web REST API creation include Express.js, Go, FastAPI, and Flask. It’s good to keep in mind, however, that API best practices can be implemented within some new frameworks designed specifically to build REST APIs. These are Falcon, Django REST Framework, and Restify.
REST API standards – why they are still worth implementing
REST is a universal style that combines the elements of various software fields, communication protocols, and distributed process paradigms. This architectural style, proper for distributed hypermedia systems, has been designed by its originator along with a set of constraints. Applying them may lead to reducing interaction latency, enforcing security, and encapsulating legacy systems. In his doctoral dissertation, Roy Thomas Fielding mentioned his initial attempts to design and deploy what was the modern Web architecture over 20 years ago. And the achievements of the future decades, like distinguishing RESTful API design best practices have made the REST API experience much smoother and fuller.
And you, which REST API best practices can you spot? Is REST API still proper for current applications? In your opinion, which REST API standards are best to follow today?
