Documenting APIs: The Guide for Technical Writers and Engineers

Whether you’re a junior developer or a team manager, there comes a time when API documentation is essential to the long-term success of your project. However, depending on the scale of the API you’re using and its back-end support, such documentation may not be readily available, leading to collective frustration.

Essentially, API documentation represents the beating heart of a development project by letting developers know how to use its feature list in an effective way. Thus, it is pivotal for teams to document their APIs’ functionality, resource base, and how they can be integrated into new applications. It takes a lot of effort to write such documentation correctly, but the long-term benefits far outweigh the initial time and resource costs.

API Stakeholders

Who are the stakeholders involved in using API documentation once it’s created? APIs are typically developed to solve different situational issues which companies and development teams face in their projects. Thus, we can categorize API stakeholders into two groups with different stakes and interests in your API documentation: project leads and users. While both are important for API developers, both have different perspectives on what an API document should look like.

Project leads are effectively in charge of deciding whether or not to use a certain API. These are typically business managers or startup CEOs. As such, their knowledge of development-level terminology and API implementation may be limited, leading to a necessary compromise in API documentation writing. Project leads choose APIs based on the project brief they have in hand and decide whether or not certain APIs are better for their needs.

API users, on the other hand, represent front-end and back-end developers responsible for developing the application, website, or service for the company. These are ground-level experts whose expertise lies in utilizing API documentation to develop relevant functions within the project. In their eyes, the more detailed and minute your API documentation, the better, which is contrary to the former type of stakeholder. Balancing both sides of the equation in your documentation writing is crucial if you wish to penetrate the market and position your API.

Writing the API Documentation

  • Implement KISS Methodology: So how do you approach writing your API documentation in practical terms? The so-called “Keep it simple stupid” or KISS methodology can be useful in appeasing the needs of both stakeholder groups. API’s documentation can be presented in an accessible manner without highly-technical terminology reserved for seasoned developers. You understand your API better than anyone else – use that privilege to communicate its functionality to others by utilizing short and informative writing.
  • Rely on Request/Response Format: Just as we use bullet points and subheadings in writing online articles, API documentation can rely on a similar format to allow for easy skimming. Developers interested in function A will search for information on function A in your API document specifically – not read through everything front to back daily. Stripe is a great example of an API document which tackles different application scenarios, error codes, and developer questions in a request/response format. By enabling your stakeholders to glean useful info quickly, you will raise your APIs utility and market value drastically compared to the competition.
  • “How to Start” Guide: While authentication, error codes, and terms of use may be pivotal to your API documentation, so is a rudimentary “how-to” guide for unfamiliar developers. You want to ensure that developers, both junior and senior, can easily handle your API in their favor without downtime. As an example, Brain Tree provides an intuitive tutorial on how to get started on their API to would-be users. Information such as basic integration, FAQ as well as your preferred SDKs can all find their way into this section.
  • On-Site Console: In order to encourage engagement and use of your API, you can write up a basic console and place it on your website. This console can be used to test your APIs code in a browser environment to quickly determine its viability for concrete implementation. You can refer to Microsoft and their console API for reference in regard to how such a function can be written for your API documentation. Facilitating experimentation and creativity for stakeholders can have a significant impact on the APIs adoption rates, especially if your brand is not yet established.

Critical API Documentation Sections

Introductory Section

When it comes to writing API documentation, make it a habit to aim for both ends of the spectrum, leads, and users alike. Your introduction can serve as a short-yet-informative description of what the API can be used for. “Writing a succinct summary of your API can be tricky since you can skip over crucial information relevant to different stakeholders. Regardless, it is an important section to start off with,” – says Dorian Martin, a tech writer at Trust My Paper and ClassyEssay writing services.

API Authentication

The authentication section represents written information on how a developer can start using the API in their project. The so-called authentication schemes give users and project leads necessary information on how the API can be implemented going forward. Omitting the authentication section in your API documentation can lead to low adoption rates due to misunderstanding and confusion about what the API can do.

Errors & Bottlenecks

No matter how well-versed a developer may be, they will undoubtedly come across bottlenecks in API implementation during development. This, writing a section specifically for potential errors for different API services should be a priority. You can use a standard error code format coupled with various explanations for different problems that may occur. It’s good practice to leave room for errors which you are unfamiliar with and encourage leads and users to ask you for more information directly.

Terms of Use

Legalities factor into API documentation as with any other openly-available resources on the web. It’s pivotal that you consult a legal expert and draft your terms of service section carefully to avoid copyright infringement. For example, a developer may use features listed in the API authentication but may not modify or any of them without your explicit say-so. Limiting your API’s commercial use will ensure that the final call for its updates, changes, and further monetization are entirely up to your team.


Lastly (or firstly, depending on your formatting choice), a changelog should be included in your API documentation writing. As the name might suggest, a changelog is used to literally “log” any changes made to the API. This is useful for developers who refer to your API frequently and may not be aware of updates to official release versions of your code.

In Summary

Even if you don’t intend to market your API commercially, writing its documentation properly will allow your in-house developers to work on projects more easily. APIs are complex, multi-level pieces of important code which can have transformative effects on any given project.

If your developers have substantial information on how API works, they can make informed development decisions as well as cut costs and spent time. Write your API documentation to further refine your workflow, eliminate bottlenecks, and enable meaningful change – the effort to do so will pay off in spades.

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