5 Most Important API Designing Principles to Keep Customers Coming Back

While starting any new web project, we can easily get lost in the hype and confusion of our technological decisions — which dependency injection framework will work best, which database to use, and which programming language will be superior. In the end, we lose focus from our aim, i.e., “developing a robust application that can effectively solve customer’s problems”. Though language and tools are an essential facet of app design , there is something more important, too, and it’s API design. Yes, API is also a vital aspect, and we tend to skip this generally.  We hardly give special attention to this area, which is completely unacceptable if you want to develop a good application.

According to the Google Trend results, we have found that every 90 out of 100 developers equally prioritize API design over other app development aspects, programming language, framework, and more.

In the end, the results were considered good only if the client finds it easy to access the app through the interfaces we have set. For this, you need an effective design. This blog will provide insights into important API design principles: Visibility, Simplicity, Error Handling, and more.

So, let’s get started with the top API effective designs.

#1. Visibility of System Status

A graphical user interface can easily confuse the users if a system doesn’t provide relevant feedback. For instance,  if a user presses a button and does not have any response from the UI, it would leave a user wondering whether they have correctly pushed the button or not. Therefore, we should provide users with all the relevant and timely information.

This type of information access is essential for APIs as well. Increased system status visibility can benefit developers, writing client applications that use API. Providing developers the more and more information will help them in understanding that what has happened while invoking API.

Providing more and better information about the system will help developers understand what has happened when they invoke the API, resulting in a better development experience.

But, yes, providing system status visibility doesn’t mean disclosing all available information about a system’s innards. From the client’s perspective, the interface, not the underlying database or code, matters more. 

For example, a client needs to know that a call may take a long time to complete, but knowing that a call is slow due to a specific database configuration sounds exciting but not helpful.

#2. Match Between System & Real World

Developing a user-friendly interface that matches the client’s business model is a crucial thing. The goal here is to reduce the things that users need to learn. In short, design an independent interface that reduces user dependencies. An interface that looks simple plus familiar to users is a key secret of developing the best application for the client.

While talking about API usability, we should care about the developer; they are our first users who will be going to use our interface. It means that the API’s language, patterns, and conventions should properly match its user’s world. It includes the tools and programming languages they use to write code, the industries and companies they work within, and the community and social world they live in today.

An API evaluator should start by knowing the targeted user of the API. If there is no user profile available, then the developer has to define it. Next, monitor the API parts that would cause unnecessary cognitive load.

For example, it may result from unfamiliar words, semantics (meanings of words) that would conflict with the user’s understanding, and message formats or message patterns that don’t fit the developer’s world perspective.

#3. Simplicity 

Simplicity provides two significant benefits: One for us and the second for the clients. The benefit that we get is that a simple API usually needs less work — less code, fewer tests, less development time, fewer errors, and less repetition. 

Whereas for the clients, the benefit is that the code where our API will go to use is simple plus smaller. However, similar to coding, the code required for consuming our APIs grows in proportion to the API’s complexity. 

To create a simple API, do follow the major basic rules:

1. Create two simpler designs unless there is a need to create a very compelling one.
2. Use primitives, like strings and numbers, as values whenever possible and include new data structures. 
3. Try to add only the important information required — future-proofing results in more code for maintenance and a larger API to use. 

#4. Consistency

When clients use our API, especially those who use them regularly, they will start to pick up on our rules and expect the same throughout the entire API. So, for instance, if we are having a REST status resource with a key and display name, we can do its representation in many ways, including as a nested object: 

Or as two different fields

We can make the right decision by considering the API’s nature and context, but whichever we will choose, stick to it and use it consistently. By staying consistent throughout the API can reap some essential benefits: 

1. Clients know our common representation, which means that the resource has the same meaning everywhere it will use. 
2. Clients can create standard code to handle the common representation. 
3. Clients can understand the resource immediately anywhere it appears, as they have already seen it before. 

Though many times, we have to bring change and use a new or different representation but limit those cases if we have a solid and compelling reason.

#5. Error Handling

We always want our app to work best and as expected every time, in real-world applications, but it’s hardly possible many times. As a result, there can be failures in both the client’s request and our generated responses.

For instance, we have designed our API to find an address linked with a registered user. Still, if there is no user associated with the supplied user ID, our API must indicate an error.

Generally, a helpful approach we can follow here is to categorize an error and provide specific error details. For example, for REST APIs, use HTTP status codes and provide error details in the response body, which means it has some error code and some supplemental data — in the header or in the message body — to determine which specific error occurred.

While we may find the error category sufficient,  there can be multiple reasons for a single error type. For instance, we pass a 401 Unauthorized response from a REST API. In such a case, a client may not know that it’s due to the incorrect user name, password, or session ID.

Knowing such information is essential if we expect our clients to handle mistakes at their level. Thus, we should always provide our clients with pertinent and detailed information about the error without compromising with simplicity.

Final Words

There is not a single approach to designing an API that will work in every project. Above I have just shared some important advice and recommendations to consider while creating your API depending upon your requirements.

Still, the process includes many small details on which you must work and deliver the desired results. However, it may alone bog us down from designing a perfect API design. 

So, instead of doing it all on our own, hire API developers; they are experienced and save your time. It will lead to better results without quality compromise.

Good Luck!

Andrej Fedek

Andrej Fedek is a digital marketer. He recently started his own blog about digital marketing called InterCool Studio. His passion is to help startups grow and thrive in a competitive environment.