API Design Guidelines – Best Practices For User-Friendly API Construction

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Superior User Experience is now possible through quality API Design Guidelines. In this blog, we will discuss the best practices for building User-friendly Application Programming Interfaces.

What is API Design?

API Design is the collection of architectural commitments, planning, and process of developing APIs that reveal data and application functionalities to be utilized by users and developers. Your fundamental API Design decides how thoroughly the developers are ingesting it, how they use it, and also how well they can interact with it. API Design enables you to add new capabilities to the processes, products, and services you provide. Our API Design guide can help you throughout your API Designing process.

Why API Design?

People often misunderstand the value of API with the value of the Organization’s core business. The Organization’s core business is more valuable. But the answer to the question “Why API Design and how is it valuable?” Is the way it acts like a channel that enables you to access the existing products and services that the organization offers.

1. Improves Developer Experience

Developer Experience is very crucial. With API Design you can make the developer tasks easy. All the organized resources make it simple to understand. It provides a detailed interaction and delivers a superior user experience.

2. Facilitates Better Documentation

Documentation plays an important role in building the interface that lets you consume the API. A strong fundamental structure boosts the process of documenting the API.

3. Helps In Better Implementation

API Design gives you a full-scale overview of all the endpoints and related operations. A constructive API can be of great help in the process of implementing complex configurations. API Design process will also help you analyze your core Product working and how your data will be distributed.

4. Facilitates Incremental Development

Your API should evolve as your products and services progress. A good API design helps you spot exactly which resource or sub-resource needs to be updated. Bigger APIs are harder to manage, with a well-designed API you can prevent repeating work by smart identification of areas that need updating.

How To Choose Your API Specification?

Planning the API spec is an important part of API development. An API spec refers to the structural look of your API, just like the blueprint of your house. Planning the API specifications can save a lot of time and also saves you from having to build a new API from the scratch. Your API requires a way to describe. You can spot any glitches or inconsistencies quickly if you go for developing your API while keeping the API specifications in mind.
Recently, the industry evolved around the OpenAPI specification which has an objective of standardizing REST API

  • REST APIs can be opted when you want to build an enduring and flexible API to plan – not just for the project roadmap or present development cycle but for the products and services that may come up a few years down the road.
  • OpenAPI v2 can serve as a contract that describes how a user can use the API and what responses you can expect. OpenAPI v2 is still a widely used API but it’s increasingly been replaced by OpenAPI v3.
  • API Blueprint was built to promote collaboration between the developers, consumers, and stakeholders. It provides a concise yet expressive syntax. It also enables you to quickly design the API to be created.
  • RESTful API Modeling Language (RAML) primarily sheds light on the planning stage of API design. With RAML you can see how your API looks, in real-time while you design it.

Also, read: “SOAP vs REST vs JSON” about different API infrastructures.

API Design Naming and Conventions

The naming of interfaces is done to deliver consistent developer experience over a long period, across many APIs. Naming Conventions ensure that the majority of developers can easily understand an API. It makes use of small, consistent, and simple vocabulary to name resources and methods.

API Naming Guides :

1. Names should be in valid English
2. You should use familiar terminology wherever possible.
3. Name overloading should be avoided, different concepts should be assigned different names.
4. Same concepts must be given the same name or term even if they are shared across the API.
5. Abbreviations of long words and commonly accepted short forms can be used for conciseness.
6. Avoid using the names or terms that may conflict with the common keywords of the Programming languages to avoid additional scrutiny during API review.
7. Don’t use general names and use specific names to avoid ambiguity within the context of API.

API Design Conventions :

1. Follow case conventions. Names of terms and protocols should be in UpperCamelCase and everything else should be in lowerCamelCase.
2. Methods can share a base name if they operate in a distinct domain or when they share the same basic meaning.
3. Free functions should be used in special cases.
4. Document the complexity of any computed property that is not O(1).
5. Use an established convention, whenever possible.
6. Take advantage of defaulted parameters when it refers to common use cases. Any parameter with a single, commonly used value is a default candidate.

API Design guidelines

These are the API design guidelines to keep in mind while designing your API.

1. Build For The Consumer:

APIs mostly never act as entry points for the users. Be thoughtful about who the consumers are, which applications of real-life are consuming your services, and build and develop the API as per the requirements of the consumers.

2. SDKs and Integrations :

API Design best practices include providing Software Development Kit (SDK) or integration to the API for any given Language. It doesn’t lead you to success directly but definitely, helps the developers in calling the API as it may also remove the business logic from the consumers’ application and makes it useful in the way it was expected to perform.

The API needs to make sense for the context. Based on work accomplished with the number of calls, APIs can be termed as follows

3. Chatty API:

API enables the developers to call services that accomplish common tasks. Some APIs need multiple calls to perform a single operation. This makes them Chatty APIs. Chatty APIs are a bad thing because it’s harder to make the same calls that should be combined and are needed to be called individually. And it is a poor thing because multiple network calls lead to applications slowing down.

4. Chunky API :

An API is said to be chunky when it does more with a single call and includes more information. Chunky API can do more in fewer calls, it can be better for your application. However there are limitations regarding how Chunky an API should be, but the useful factor is to include all the useful information for high-end services.

5. Good Documentation Prevents Guesswork for Your Users :

Good documentation enables your users to know the purpose of each call, and how to be more productive with little calls. Good documentation also reduces the support costs from repeat questions.

6. Version Your APIs :

Versioning your API helps you to ensure the backward capability of a service to add a new feature for clients. Though beware many different thoughts to version API, most of them fall under the following two categories.
Custom Header: Service can route the requests to the correct endpoint of API by using a custom x-API-version header key by the client.
Accept Header: using accept header to state your version.
=> Accept: application/vnd.hashmapinc.v2+json

7. Using HTTP Status Codes :

Using HTTP Status Codes to deliver the response to the client. Be it a successful response or a failure response, it should be able to explain the respective responsibilities and what it means from the server perspective. Following are the response categories by their status quotes.

Categories of responses with their status codes are mentioned below.
2xx success: 200 Ok,201 created
3xx Redirection: 304 Not Modified
4xx Client Error: 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 not found, 405 methods not allowed.
5xx server errors: Due to server failures or issues related to the underlying infrastructure.

8. Clarity At The Point Of Use :

It is an essential goal, structures like methods and properties are declared only once but can be used repeatedly. Your API design should make these uses concise and clear. Reading a declaration is hardly sufficient in gauging an API Design. You should ensure that your API looks clear in context, examining a use case can help you regarding this.

9. Prefer Clarity Over Brevity :

The goal of API design principles is not to enable the smallest code with the fewest characters possible. Clarity is preferable but not at the cost of uncertainty. Maintain internal consistency and approach design collaboratively.

10. Don’t Misuse Safe Methods :

HTTP methods return the same resource representation every time they are called by the client. Safe methods such as GET, HEAD, TRACE, and OPTIONS are intended for data retrieval and they don’t change the state of any resource on the server. Use these safe methods according to the action required to be performed, without violating the HTTP specifications.

11. Return Representation :

Methods like PATCH, PUT, and POST are used to update fields in a resource, should return updated resource representation every time as a response, along with appropriate status code.

Considerations For The Build Process Of API Design

What is the Slowest Part of an API?

No beating around the bush, the network time is the slowest part. That means the report generation will compute the report instead of network time.

What will the user want?

As API is a service that should do more than returning a Database object. Here, what can help your users a lot is good documentation. Send as little data as possible but not less data. Don’t inflate your response with information not relevant to the calls related tasks.

Which information should I group?

Ultimately, your API should be accomplishing the common tasks. It is a good practice to bundle multiple calls which are often in conjunction. This will harden the work of the users who don’t do multiple calls, making sense. And grouping of protocols is a part of API design but it is your choice.

Are You Ready To Build Better APIs?

APIs serve with the basic objective of giving the ability to the users to complete common actions easily with as few calls as possible. It’s not right if the users have to make 4 or 5 calls to create a single user. When the users are returned with huge payloads of worthless information, it’s most probable that these payloads of information should be split for accomplishing different tasks.

In case the users have to work on debugging the errors from the payloads then the requests have to be updated to return appropriate error codes, this saves the developers’ time as they can know what went wrong instead of debugging the issue present on the server for long durations. As we discussed earlier, APIs make the lives of developers easy. APIs have to grant high-level access to the developers to use but they deal with low-level information or objects.


The most important service providers always design high-quality and consistent APIs. Performance of the API is crucial, it should be efficient so that you don’t have to query for data all the time. In this blog, we have discussed the important principles of API design and API best practices etc which can assist you in designing a robust API.

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