9 Best Practices to Follow for a Perfect RESTful API Design

APIs are transforming digital ecosystems by connecting modern applications with each other for delivering smarter and personalized user experiences like never before. 

They enable businesses to increase revenue and add value to products; which is why most successful businesses have a well-planned API-driven strategy in place.

RESTful APIs are currently the trend in API development because of the level of flexibility it provides compared to other alternatives. But, how to design and build a high-quality REST API that delights end developers and is easy to maintain? What are the best practices to be considered while designing RESTful APIs?

Let’s find out!

1) Employ JSON for Requests and Responses

REST supports various output formats like JSON, HTML, XML, RSS, CSV, et. al. But, it’s advisable to choose JSON for transferring data; i.e, for both payloads and responses.  Most back-end technologies have in-built mechanisms to decode JSON quite easily.

However, to ensure that a client or service interacting with the API correctly decodes a JSON response, specify the Content-Type in the response header and once the request is made, set it to the value, application/json.

2)  Avoid Using Verbs at API Endpoints

RESTful API development is based on resources and collections, and the state of a resource is defined by HTTP methods ( verbs) like:

GET – fetches a resource

POST – creates a new resource or submits new information to the server

PUT – replaces a resource

PATCH – updates an existing resource

DELETE – removes a resource

Now, it’s important that you don’t write verbs in the API endpoints. For example, to create a new report, it’s enough to write POST: /reports/ and not POST: /reports/createNewReport/.

The rationale behind this is to make the code look simple and reduce ambiguities; the HTTP method is already defined and it will completely perform the action that is required. So, there’s no need to add an extra verb in the endpoint for getting the action done.

3) Apply HTTP Verbs Correctly 

It’s a common tendency among developers to mix up HTTP verbs for different actions. Very often, POST request is used to retrieve data or PUT request is used to update data. Do not attempt this kind of manipulation as it can create confusion in the minds of developers.

4) Use Plural Nouns for Naming Collections

As seen in the previous example, a plural noun is used at the API endpoint. The same convention applies to naming collections too; using plural nouns will give the idea that the database has a set or collection of entries. 

Sample this: 

GET: /reports/4/ and GET: /report/4/

The first command instructs to fetch the report with id 4 from a collection of reports. The second command gives us an ambiguous feeling that there are not many reports in the database.

5) Allow Filtering, Searching, Sorting and Pagination 

An effective RESTful API should have built-in capabilities to handle actions such as filtering (to generate results based on specified parameters), searching (to display results based on a particular input), sorting (to arrange queries in ascending or descending order) and pagination (to retrieve parts of a data set). 

For this, a query string has to be added to the API endpoint that is being called.

Examples:

Filtering – GET: /authors?book=1984 

Searching – GET: /authors?search=Catherine

Sorting – GET/authors?sort=name:desc

Pagination – GET /books?limit=30&offset=50

Click here to know more about the different  methods of pagination and how each one of them are implemented in the Django REST framework.

6) Handle Errors Properly

Occurrence of error(s) cannot be overruled in a client response and the key is to adopt standard HTTP error handling methodology to tackle it. Take the case of how Twilio returns the details of an error:

{

    “status”: 400,

    “message”: “Resource articles does not exist”,

    “code”: 25601,

    “more_info”: “api.com/docs/errors/25601”

}

The server returns a status code (400 – which indicates ‘Bad Request’) accompanied by a readable message that describes the error and the internal error code (25601). This format of error handling helps developers to debug faster as the specific information regarding the error is made available in the response.

7) Utilize Meaningful HTTP Status Codes

There’s no denying the fact that HTTP response status codes are as important as error messages. That’s why, status codes have to be used consistently and also, correctly because, you don’t want to see a response returning an error message along with a 200 OK status code (instead of 4xx codes).

Do check out the comprehensive list of status codes at the Mozilla Developers site.

8) Make Versions of the API

API versioning can be implemented, as it is an effective strategy that allows users to easily adapt to breaking or non-breaking changes done to specific actions or data structure.

There are generally two methods to implement versioning:

• Through endpoint URI 

https://api.example.com/v2/

http://apiv1.example.com

example.com/api/articles?version=4

• In a custom request header 

Accept-version: 3

Accept: application/vnd.example.v3+json

Accept: application/vnd.example+json;version=3.0

Last, but not the least,

9) Follow API Security Practices

Securing your API should not be overlooked, because no matter how hard you try to stick on to the API guidelines and best practices, a single cyber attack is enough to make your efforts go in vain.

Some of the practices that can be adopted for enhancing API security are:

• Encrypting communication between client and server using SSL/TLS.
• Authentication using OAuth2 and tokens.
• Daily and monthly quotas for API requests per client.
• Rate Limiting and Throttling – for controlling the number of requests of each API client.
• Gateways – for handling API traffic.
• Input and Resource Validation.

Conclusion

The true success of a RESTful API depends on how the end users, i.e; developers/programmers receive it. The above listed best practices will help, to a great extent, to design a developer-friendly API, that’s simple, clean and reliable.

Hope you enjoyed the article and if you need any assistance regarding integrating API into your app or want to build an API from scratch, don’t hesitate to hire the best API development company for your next project.