Application Programming Interfaces (APIs) can only be as good as their documentation. If you have a great project but you do not provide elaborate API documentation on how to use it, then it’s all useless!

APIs are intended to be consumed. Therefore, it’s pivotal to ensure that users can quickly get started in implementing them without many hurdles. Unfortunately, most APIs are poorly documented, which complicates their integration and defeats the very purpose of their existence.

In this article, we’re going to talk about the best practices that will ensure you know how to write API documentation.

What is API documentation?

API documentation is a reference document that outlines how to make use of the API. It’s a technical manual that contains information about the services the API offers, how to use its various endpoints and parameters, and other implementation instructions.

APIs allow developers to transmit data between software products easily. With an API, you can fetch the features of a product and integrate them into your application, without the need of starting from scratch.

With good API documentation, developers can understand the usage of an API and incorporate it into their use cases without experiencing programming obstacles.

Why is API documentation important?

Best API documentation is key to enhancing the developer experience. Developers tend to be very demanding people and they are unlikely to spend countless hours trying to get started implementing your inconsistent and incoherent API.

If you get your API documentation right, many developers will find it easy to use, leading to increased adoption of your products and services.

Furthermore, well-explained documentation saves support time and costs. With good documentation, your team is likely to spend less time onboarding new users and responding to support calls and emails.

Improperly written REST API documentation template implies that more frustrated users will depend on your team to assist them in integrating your API, which increases your operational costs.

Best Practices for Documenting APIs

Here are 5 of the best practices on how to write API documentation:

• Plan for your docs
• Include fundamental sections
• Be consistent and avoid jargon
• Include interactive examples and other resources
• Maintain your docs

Let’s now talk about each of the ways on how to document an API.

1. Plan for your docs

“Failing to plan is planning to fail,” so goes the famous quote. Definitely, if you fail to plan ahead for your documentation exercise, then you may not be successful with it.

Before embarking on documenting REST API, you should know who you are creating the docs for. If you know the audience your writing will address, it’ll assist you to decide on the language, structure, and design of your documentation.

Who visits your sample API documentation web page?

What do they intend to use it for?

Understanding the purpose and scope of your documentation will help you to craft useful content that enhances the consumption of your API. Creating your API document with user experience in mind allows you to structure it in manner that addresses their needs.

After all, they’re the people who are going to read it. So, the best way to document REST APIs is to understand users’ needs.

2. Include fundamental sections

There are sections that have become necessary to authoring great API documentation. These fundamental sections are essential for enhancing the readability and adoption of your API. You can tailor them based on the needs you want to address with your documentation.

Here are some of the most pivotal sections in any API documentation template:

• Overview: Including an overview section assists in conveying what your API is about quickly. This opening section can be vital in introducing the user onboarding process and detailing the pertinent attributes of your API. If you can show users a quick win in this section, you’ll have grabbed their attention to continue reading through the rest of the API reference documentation. For example, here’s how AccuWeather does it:

• Authentication: APIs that require authentication need to have a section that clearly explains how to get the access credentials and how the keys work for making requests. Since authentication is one of the initial biggest obstacles to the successful consumption of your API, you need to get it right—the first time.
• Resources: The resources section forms the core component of your API doc. Since users are likely to interact more with your API’s resources, and their corresponding requests and responses, it’s important to provide all the necessary information about them. All endpoints, parameters, and other details should be properly documented.
• Error messages: If you offer useful, human-readable information about the possible error messages a user may encounter when interacting with your API—besides just correct error codes—you’ll allow users to learn and integrate your technology easily. You should also include explanations on how the errors can be solved.
• Terms of use: This section acts as a legal agreement that outlines how users should ideally consume your services. You can include terms and conditions, best use practices, rate limits, and usage constraints.

3. Be consistent and avoid jargon

Another best practice for writing API docs is to maintain consistency in the use of terminology throughout your documentation. Your write-up should be entirely uniform and without contradictions in language and code. You should sufficiently proofread your documentation to eliminate sections that are ambiguous or difficult to understand.

It is also important to be consistent with universally-accepted naming conventions and terminologies. Whereas you have the freedom to decide on what goes into your code, trying to be excessively creative on the use of status codes, HTTP verbs, and other conventional item names may lead to unnecessary confusion.

For example, when writing a REST API documentation, the GET HTTP verb should always be utilized to retrieve data from a stated resource. Sticking to such well-established conventions will save you the hassle of writing many explanations, making your documentation easier to understand.

Furthermore, you should keep the docs free from unnecessary technical jargon, as much as possible. Your technical writing team may be tempted to use complicated or domain-based jargon; however, it’s in your best interest to use a language that is simple and resonates with the needs of your users.

Assuming that your audience is completely technical and understands how APIs work is a big mistake. A good documentation should be easily understood by people new to the API economy.

If there is a technical or a domain-based jargon, you can provide links to further documentation that explain their meanings. Remember that humans are the primary readers of your API reference documentation, and not machines.

4. Include interactive examples and other resources

More than anything, most developers like when they can test what they read in the documentation and see how it works. If you can include interactive sample codes in the most popular programming languages, it can greatly reduce the friction in implementing your API.

Providing interactive demos is a powerful way to improve the learning curve of consuming your API. For example, you can include a sandbox environment filled with test data so that users can run requests and see the types of responses returned.

For example, the Deezer API allows you to test its endpoints and get responses right away.

Here is its screenshot:

Furthermore, you can supercharge your API reference documentation by adding other useful resources. These extra information and resources can help users to make the most of your API—beyond the provided documentation. With the best API documentation tool, you can add the materials easily.

Here are some resources you can use to supplement your API document:

• Getting started guide: Including a guide as a quick way to show users how to get started in fetching the features of your API can greatly assist in its adoption. Users are likely to get interested in your offerings after they’ve tried and experienced an initial success with how the API works.
• SDKs, libraries, and tutorials: These additional resources can offer step-by-step walkthroughs about how developers can integrate the API in various scenarios while using their most comfortable programming language. Having code libraries and SDKs is an awesome method to engage with developers and enhance the API adoption.

5. Maintain your API docs

Ensuring your docs remain accurate and up-to-date is critical for its success. If your API descriptions are obsolete, users can get frustrated and lose trust in your services.

Here are some things you can do to maintain your API docs:

• Remove descriptions of deprecated features. If a feature has been removed from your API, take it from the documentation and explain the reasons behind the decision.
• In case any new feature has been introduced into the API, ensure it’s properly and timely documented. You can also version the API document to reflect the newly added features.
• In case you get any feedback, act on it appropriately to improve the quality of your API reference docs. You may not get your documentation right at the first try, but if you listen to feedback, you can continuously make improvements to it.

Conclusion

Knowing how to write API documentation is not a walk in the park. Creating excellent API reference documentation requires hard work and commitment.

However, if you can put in the hours, you can craft awesome documentation that can spearhead the growth and adoption of your APIs.

We hope that the above best practices will make your journey to writing great documentation easier and fulfilling.

All the best.

About Rakuten RapidAPI:

Rakuten RapidAPI is the world’s largest API marketplace with 8,000+ third-party APIs and used by over 500,000 active developers. We enable developers to build transformative apps through the power of APIs. Find, test and connect to all the APIs you need in one place!

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