REST API Best Practices and Standards in 2023

Mastering the REST API Best Practices is an art! APIs are used by every software professionals, but not everybody can write the best ones. The security concerns of people because of the poorly written APIs need attention. When you are designing REST APIs, these REST API Best Practices will help you to elevate your API writing skills. As a REST API designer, writing an effective API will make your work easier.

In this blog, you will be introduced to REST API along with REST API standards. The working and characteristics of REST API are elaborated. Ten REST API Best Practices with examples will be discussed.

Table of contents

• What is REST API?
• REST API standards
• Working of REST API
• Characteristics of a well-designed API
• REST API Best Practices
  • REST API Best Practices: Prioritize Nouns over Verbs
  • REST API Best Practices: Prefer using Plural naming conventions
  • REST API Best Practices: Utilize Resource Nesting Efficiently
  • REST API Best Practices: Systematic Documentation
  • REST API Best Practices: Data Filtering options
  • REST API Best Practices: Utilize SSL/TLS security layers
  • REST API Best Practices: Focus on Error Handling
  • REST API Best Practices: Always choose JSON
• Conclusion

What is REST API?

REST API is an API that follows a set of rules for an application and services to communicate with each other. As it is constrained to REST architecture, REST API is referred to as RESTful API. REST APIs provide a way of accessing web services in a flexible way without massive processing capabilities.

REST API standards

The API best practices and standards are a must-follow for all the REST APIs. The REST API standards have a list of constraints to abide by. These REST API guidelines and constraints are explained below.

1) Statelessness

Systems aligning with the REST paradigm are bound to become stateless. For Client-Server communication, stateless constraint enforces servers to remain unaware of the client state and vice-versa. A constraint is applied by using resources instead of commands, and they are nouns of the web that describe any object, document, or thing to store/send to other resources.

2) Cacheable

Cache helps servers to mitigate some constraints of statelessness. It is a critical factor that has improved the performance of modern web applications. Caching not only enhances the performance on the client-side but also scales significant results on the server-side. A well-established cache mechanism would drastically reduce the average response time of your server.

3) Decoupled

REST is a distributed approach, where client and server applications are decoupled from each other. Irrespective of where the requests are initiated, the only information the client application knows is the Uniform Resource Identifier (URI) of the requested resource. A server application should pass requested data via HTTP but should not try modifying the client application.

4) Layered System

A Layered system makes a REST architecture scalable. With RESTful architecture, Client and Server applications are decoupled, so the calls and responses of REST APIs go through different layers. As REST API is layered, it should be designed such that neither Client nor Server identifies its communication with end applications or an intermediary.

5) Client-Server

The client and server applications must be able to function without the help of each other. Both the server application and the client application must abide by the separation of concerns agreement. By this agreement, when altering the client end, there should not be any impact on the server application. And also, when the code of the server is altered, it should not affect the client end. This enhances the scalability and flexibility of the interface across platforms.

6) Code on demand (optional)

Of all the constraints, this one is optional. The usual format used while sending resources is JSON REST API or XML. But whenever it is required, you are provided with an option to return executable code. This will support the main part of your application.

Working of REST API

A REST API requires a host URL that acts as the primary address for your interactions. REST APIs also need a set of endpoints, which are unique addresses within-host URLs responsible for its functionality. Moreover, it is a good practice to document the endpoints, return value, data types, and other essentials of a REST API. 

The below diagram is a high-level representation of the required organization of your code to create a REST API. You may have one or more databases that contain data that other applications might need. So, they will use the REST API that uses SQL and JDBC to interact with the database. REST APIs enable you to centralize all your basic logic in one place instead of rewriting it every time you want to create a new app as shown by the below image. 

Now, APIs are designed to return the required data whenever a user calls them. However, when you use REST APIS, it not only returns the requested data but also presents it in a well-structured form for representation. A REST API utilizes a client-server architecture that allows different applications to communicate. The client software makes a call to the server application using a REST API. The Server application sends the requested data in a structured form organized using key parameters over the HTTP protocol.

Characteristics of a well-designed API

• Flexible: REST API is flexible with multiple types of calls like returning different data formats and changing structurally with the correct implementation of hypermedia. It allows users to communicate back and forth with clients and servers, even if they are hosted on different servers.
• Adaptable: REST API is adaptable to any modification done in data that resides in the database, even when hosted on the different back- and front-end servers. Since it depends to a certain extent on codes, it helps synchronize data within websites without any issue.
• Ease of Understanding: As REST uses HTTP verbs (GET, POST, PUT or DELETE) methods for communication, these methods are self-explanatory. In addition, REST architecture helps increase developers’ productivity, allowing them to display the information on the client-side and store or manipulate the data on the server-side.

REST API Best Practices

While designing REST APIs, you need to focus on all these best practices to make your REST API the best. As a REST API designer, you must focus on the safety as well as the working of the API.

REST API Best Practices: Prioritize Nouns over Verbs in URI

Since REST API is mostly developed for resources like services, it is essential to use Nouns and not verbs. So it is better to use only Nouns to represent an entity in REST endpoint paths. This is because the HTTP request method already consists of verbs. So having verb in REST API endpoints will not pull any new information. You must use tags to change the resource’s state.

The following table helps you in understanding the REST API Verbs:

REST Verb	Action
GET	Fetches a record or set of resources from the server
OPTIONS	Fetches all available REST operations
POST	Creates a new set of resources or a resource
PUT	Updates or replaces the given record
PATCH	Modifies the given record
DELETE	Deletes the given resource

Here are a few examples to show how the endpoints should look like,

• GET/books/123
• DELETE/ books/123
• POST/books
• PUT/books/123
• PATCH/book/123

REST API Best Practices: Prefer using Plural naming conventions

Generally, it is the best practice to use plural nouns for collections. This plural naming convention becomes a global code. This also helps normal people to understand that these groups of APIs form a collection.

The following table helps you in understanding the right and wrong usage of plural names in REST API :

Do’s	Dont’s
GET/bikes/123	GET/bike/123
POST/bikes	POST/bike
GET/bikes	GET/bike

REST API Best Practices: Utilize Resource Nesting Efficiently

Resource nesting is a practice of clubbing two functions that have some hierarchy or are linked to each other. Nesting to one level is one of the best practices to group resources that are logically coherent. For example, ‘order’ and ‘users’ are two resources of the same category in an online shop. The ‘user’ makes the ‘order’ and the ‘order’ belongs to the ‘user’. The following code explains the scenario discussed above.

/users // list all users
/users/123 // specific user
/users/123/orders //list of orders that belong to a specific user
/users/123/orders/0001 // specific orders of a specific users order list

Overusing Nesting is not good in any case. When overused, Nesting loses its appeal and creates unwanted dependency issues. So the REST API best practice that can be followed is limiting the use of nesting to one level.

REST API Best Practices: Systematic Documentation

Another important REST API best practice is to document all the solutions in a very systematic manner. The utilization of framework, application, or software usage requires proper documentation. This document will act as a reference while troubleshooting an issue. This API documentation needs to be precise and simple enough for non-technical people to understand it. Doing such systematic documentation will help your users indulge and understand all the necessary aspects like error handling, security, and authentication.

REST API Best Practices: Data Filtering options

When the database grows, it becomes a great challenge to manage it. The main challenge in this huge database is to retrieve only the requested data. The entire database should not be exposed while retrieving data. For fulfilling this, you need to use a filter that will pull data that satisfies the required criteria. By filtering the data while retrieving, huge bandwidth is saved in the client’s end. REST API provides you with 4 types of filtering options. The REST API filtering options include:

• Filtering
• Sorting
• Paging
• Field Selection

Filtering

Using this you can filter results that satisfy your required conditions. You can use search parameters like country, creation, date and etc for this.

ET /users?country=UK
GET /users?creation_date=2021-10-11
GET /users?creation_date=2021-10-11

Sorting

You can sort your results in ascending and descending order using this option.

GET /users?sort=birthdate_date:asc
GET /users?sort=birthdate_date:desc

Paging

Using the ‘limit’ option, you can narrow down the results to the required number. You can also use ‘offset’ to show the part of the overall results displayed.

GET /users?limit=120
GET /users?offset=3

Field Selection

Using the field selection function, you can request to display a specific part of the data available for that object. While you query an object with many fields, you can specify the fields in your response. An object will have ‘Name’, ‘Surname’, ‘Birthdate’, ‘Email’, ‘Phone’ as its fields.

For example, when you want to retrieve the birthdate and email to automate birthday wishes. You can use a query like this:

For a specific user:

GET/  users/123?fields=name,birthdate,email

For a full list of users:

 GET/ users?fields=name,birthdate,email

REST API Best Practices: Utilize SSL/TLS security layers

One of the REST API Best practices is to encrypt the communication using SSL/TLS. It is very essential to ensure database security for any API developer. The earned trust of the customers to keep their sensitive details private is a must. To avoid security breaches, you need to use SSL (Secure Socket Layer) and TLS (Transport Layer Security). SSL/TSL provides a public and private key to give a secured connection. TSL is an advanced version of SSL and hence provides better protection and security.

REST API Best Practices: Focus on Error Handling

Handling error with care is one essential skill of an API developer. The HTTP error code will point to the nature of the individual error when the API is effective. REST API has 71 unique errors with HTTP status codes with error messages. Along with the standard error handling of HTTP statuses, and elaborated message on the internal code will help the user to understand better.

Idel error handling code consists of 3 parts:

• Error – a unique identifier of the error
• Message – a comprehensive, readable message
• Detail – lengthier explanation of the message

For example, when you receive a login response with an incorrect password, you can send a 401 response with a code like this,

{ "error": "auth-0001", "message": "Incorrect username and password", "detail": "Ensure that the username and password included in the request are correct" }

REST API Best Practices: Always choose JSON

JavaScript Object Notation is one of the easiest languages and an easy-to-use format. One of the important best practices to follow is to always choose JSON. The key feature of JSON is that it is very easy to parse and supports most frameworks. JSON can be used by any programming language.

Conclusion

From this blog, you would have learnt about REST API along with REST API standards. The working and characteristics of REST API will be clear to you now. Ten REST API Best Practices with examples are all yours. What are you waiting for! Use them and master this ART. Hevo’s native REST API connector can help connect with a variety of non-native/custom sources into your Data Warehouse to be visualized in a BI tool.

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