Consistency is everything when it comes to APIs. Having to comb through all of your code and data by hand in search of irregularities defeats one of the primary purposes of using APIs in the first place. Standardization is the key to ensuring consistent results.

This gets tricky when consuming data from various sources in different formats. Even internal APIs may be developed in wildly different styles. As such, API design style guides are one of the best ways to ensure consistency among all of our APIs and data.

It’s hard to know how to create an API style guide out of whole cloth, though. Examples give us something concrete to model our own work after. In that spirit, we’ve pulled together some examples of good API design style guides that we’ve found to give you some ideas on how to style your own APIs.

7 API Design Style Guides

Agenzia per l’Italia API Design Style Guide

Our first example was discovered in the API Stylebook, an absolutely essential resource if you’re looking for API design style guides to model your work after. The design guide comes from the Agenzia per l’Italia Digital, which translates to the Agency for Digital Italy, an organization created by the Italian government to help foster the highest level of technological innovation from Italy.

As one might expect from a government agency, the guide uses a high level of detail. They not only delve into technical minutiae on the official policy on different protocols like REST and SOAP, but they also explain official policies regarding naming resources, what kind of data can be returned, and what type of HTTP methods are allowed.

The API Stylebook is a great place to start when you first begin researching API style guides, as they break the original documents down into standardized subsections. These subsections are browsable, as well, allowing you to see different examples of data governance for instance. This gives you ample criteria on which to base your API style guide.

Adidas API Design Style Guide

Next, we turn from a government agency to the private sector. Adidas’ API Design Style Guide is a model of clarity, making it ideal for API designers and developers who aren’t that familiar with technical writing and documentation.

Adidas’ style guide details everything from acceptable API specifications to the official policy on API-first design. It also dictates their stance on versioning and how much API surface to expose.

Even better still, the Adidas API Design Style Guide is hosted on GitHub, further emphasizing a consistent and uniform format that most developers are familiar with. It also makes the documentation readable via GitBook, to give you an example of what clean, clear, straightforward API documentation looks like.

We discovered the Adidas API Design Style Guide within another excellent repository of API design style guides maintained by Erik Wilde. Spend an afternoon browsing this extensive listing, and you’ll be close to an API design expert in no time.

Stoplight API Design Style Guide

If you want to see API style guides done right, you’d do well to check in with the creators. Stoplight is a collaborative API design platform that gets everyone working on an API on the same page. They offer Public Style Guides as part of this mission, allowing users to create API style design guides with a few simple clicks.

Having simple, streamlined forms to fill out and follow makes creating your own API design style guides, which they also refer to as API guidelines, as simple as connecting the dots or filling in some blanks.

Even better, they share their own API style guide to give you a concrete example of API guidelines to base your own documents after.

Even reading through their landing page will give you a great idea of what to include with your own API guidelines. They specify everything from guidelines on naming endpoints to which HTTP error codes to use.

Atlassian API Design Style Guide

Here’s another collaborative platform with an excellent API style guide. Atlassian has been working towards creating consistent REST APIs across its entire organization. Atlassian’s API design style guide lets you learn from their hard-won wisdom and experience.

Not only is it an excellent guide to base your guidelines on, but their notation also gives you some additional ideas to consider. For example, the Using These Guidelines section provides examples of edge cases and what to do when you encounter them.

The world is not black-and-white, and nothing’s ever going to follow guidelines exactly. Seeing an example of what happens in the case of exceptions will help you prepare for the inevitable edge cases.

Heroku API Design Style Guide

As a cloud-based application environment, APIs are vital to Heroku’s functioning. They have more incentive than most to have a clear and robust API style guide. That in-and-of-itself makes Heroku’s API design style guide worthy of a look.

Heroku’s API design style guide is hosted on GitHub, for one thing, which automatically delivers a uniform format that most developers are familiar with, and means that it’s browsable via GitBook. The guide is also written in plain and understandable language, making it useful for developers and laypeople.

Heroku’s API design guide offers an excellent example of how nothing is left to guesswork in quality documentation. For example, the manual specifies how to name endpoints and attributes, for example. Similarly to Atlassian’s guide, Heroku developers have considered many extenuating circumstances and accounted for them within the style guide.

Last but not least, Heroku’s API style guide is worth emulating for its detailed summary alone. Much more than a Table Of Contents, its headers and subheadings make it sound as a style guide in its own right. Then you can click through if you want more details.

GitLab API Design Style Guide

GitLab’s style guide is as clear and as eloquent as the rest of the style guides on our list, but that’s just the start. It’s mainly noteworthy for its detailed code snippets and examples, though. Even better still, the code is hosted on GitHub as well. Doing so could make it easier for developers to copy and paste examples into their development projects. All of this together makes GitLab’s API design style guide an excellent example of practical documentation that’s well worth emulating.

Apiary API Design Style Guide

Let’s round out our list with one last collaborative platform. Apiary is another platform that lets collaborators easily design and deploy APIs. In addition to offering excellent examples of explicit and straightforward API design style guides, its uniform format even offers developers real-time feedback on their APIs as they’re being written.

Apiary’s API design style guide offers some excellent real-world examples of their APIs, making these concepts more concrete and less abstract. It’s easier to picture a style guide’s usefulness when you see it in action. Even Apiary’s layout gives you some ideas on how to put these ideas into practice, as the standardized format allows for a slick, modern display similar to what we saw earlier with GitBooks.

We’re closing out with Apiary as it offers an example of what’s possible with an API design style guide in place. When all of your APIs follow a uniform and consistent format, it’s easy to implement API documentation automation, for example. It also helps to make your APIs as secure as possible.

API Design Style Guide: Final Thoughts

The world is only going to keep getting more complex. Businesses and users generate increasing amounts of data with each passing year. It is estimated that there are 44 zettabytes of data as of 2020. Just think about what will happen with the increasing proliferation of the Internet of Things and more of the world’s population getting online.

With this amount of data and complexity, it’s imperative not to leave technology designs to chance — that’s a recipe for disaster. Something as simple as an API design style guide can make the transition as easy and seamless as possible before the floodgates open. Designing consistent APIs dramatically reduces the risk of APIs breaking and causing service outages.

Yet, technical documentation can be prohibitively dense and vague, especially when you’re first getting used to the language and format. Having many examples to compare, contrast, and take inspiration from will get you thinking like an API designer as quickly as possible.

For more ideas and inspiration for creating your own API style guide, read our tips for creating an API design style guide. We’ve also covered plenty of other API best practices, REST design tips, and specific naming conventions.