An API is only as good as its documentation. API documentation is essential for an API’s usefulness, as it dictates everything from API discovery to onboarding new users. It’s often a user’s first exposure to an API, making API documentation a critical contact point for establishing and solidifying a company’s reputation.

API documentation is your first chance to make your API stand out in the marketplace. It also helps ensure that your API is actually usable and useful for your users. It’s a bit like a website, landing page, and instructional manual all rolled into one. That means all the rules of good copywriting apply, as do the guidelines for writing good technical writing.

With that in mind, here are ten tips for writing excellent API documentation.

1. Decide On the Type of API Documentation

Reference API documentation is the first and most common type. It’s essentially the instruction manual for your API, covering everything from API structure to syntax to common returns and requests.

Tutorials provide step-by-step instructions for how to use your API or specific tasks. Tutorials are often included as part of API documentation.

Conceptual API documentation is almost the opposite of tutorials. It looks at your API from the highest-possible level, frequently organized by topic. Conceptual API documentation is an excellent choice if you’re creating documentation for a series of APIs.

2. Look At Other Documentation

There’s no need to reinvent the wheel when creating your API documentation. There’s a world of excellent API documentation examples to learn from. Twilio’s API documentation, for example, is a masterclass in clean, clear, well-organized, and logically constructed API documentation. It’s also a good example of conceptual API documentation, as it features documentation for a wide range of APIs.

The API documentation for Slack is a prime example of easily understandable documentation that is also beautifully designed. Or, the Google Maps API documentation is another good example of thorough, well-presented API documentation that conveys a lot of information on one page.

3. Improve Your Understanding

Before you begin working on your API documentation in earnest, spend some time with the API and make sure you really understand it. The more in-depth your understanding is, the easier time you’ll have explaining it to someone else.

If you truly understand something, you should be able to explain it to absolutely anyone, regardless of their technical proficiencies. This way, there’s no barrier to API adoption, no matter their programming experience. Understanding your API thoroughly will help you lay out your API documentation, too, from structuring your documentation to offering useful, practical examples.

4. Come Up With A Plan

In business, winging it is never a good idea. Writing API documentation is no exception. If you don’t put a plan in place, it’s easy for things to get overlooked. It can also make the process take longer than it should.

Similar to an API design strategy, putting an API documentation strategy in place ahead saves time, energy, and resources in other ways, as well. Creating user profiles will help you tailor the language of your API documentation to your audience. It can also help answer structural questions, like what format to use, where to host it, and if it’s intended for public or private usage.

5. Include the Necessary Info

Much of the best API documentation features the same sort of information. According to Smartbear’s State of the API Report, developers want the following in their API documentation:

• Examples (70%)
• Status and Errors (51%)
• Authentication (50%)
• Error Messages (49%)
• HTTP Requests (44%)
• Parameters (40%)
• Getting Started Guide (38%)
• Methods (37%)
• Code Samples (35%)
• Tutorials (35%)
• Resources (22%)
• Sandbox Environment (22%)
• SDKs (15%)
• FAQs (10%)
• Rate Limiting and Thresholds (10%)
• Glossary (7%)
• Other (.4%)

6. Include An Onboarding Section

A best practice for API documentation is to include a section giving developers everything they need to quickly get started with your API. This should include everything from information regarding the libraries they’ll need to install to code snippets for some of the popular programming languages so users can try out your API for themselves.

For this reason, an onboarding section is an excellent place for a code sandbox. With it, users wouldn’t even have to open up a separate terminal to try out your API. The onboarding section often features all the materials a user needs to get started with authorization, authentication, and security protocols.

7. Practice Consistency

Consistency will make your API documentation much more straightforward and useful. It removes potential confusion by sticking to one naming convention and using it throughout.

Make sure to give your API documentation a solid read-through before publishing, looking for grammatical issues, incomplete thoughts, and awkward transitions. If possible, the best way to avoid inconsistency is to create an API style guide before you begin.

8. Avoid Jargon

Excessive use of jargon unnecessarily limits your audience and user base. Not every API user will have experience using APIs or programming — especially now that APIs have become so widespread.

Limiting jargon is a good rule of thumb and practice for technical writing. It makes your documentation clearer and more understandable and can also make it more interesting and engaging. It’s a good idea to review your API documentation with an eye out for jargon. If you find any, ask yourself if it’s necessary or if a more general term could replace it.

9. Use Interactive Examples

Offering interactive examples in your API documentation provides an excellent opportunity to see your tech in action. It also makes your documentation more engaging to help your API stand out from the competition.

Including interactive examples in your API documentation lets users see concrete, practical uses for your API, which will help give them some ideas of how it might fit into their existing workflow. It also reduces the learning curve for your API so that people can get started with it quickly and easily.

10. Maintain Your Documentation

Creating good API documentation is essential. Keeping it up-to-date and relevant is just as important, if not more so. Outdated documentation can suggest that an API is no longer being maintained, causing users to seek out a more relevant tool. Outdated or broken features can negatively impact your company’s reputation, as well.

Updating your API documentation should be a part of any API versioning process you undertake. You can outline and provide details on any changes you’ve made and why. You can also specify any removed features or functionality and include any workarounds that might be needed.

Hosting your API documentation online is an excellent way to ensure that your API documentation is always up-to-date and ready for use by your customers and users.

Final Thoughts On Writing Great API Documentation

Writing great API documentation is almost as important as creating good APIs. In some regards, it’s even more vital as it’s how your API is likely to be found via search engines and user shares. It’s also one of the most crucial elements for people to actually use your API, as it’s the central place where users will come for troubleshooting and practical examples.

If you’re serious about making your API its best and succeeding in the marketplace, give plenty of attention to your API documentation alongside development and marketing.