How to Write API Documentation in 6 Simple Steps
You tap on your smartphone’s weather app, and a few seconds later, you see the latest weather updates for your location. The smartphone weather app does not store the weather data, nor does your smartphone. So, where did the weather data come from?
The ride-hailing apps you use do not have real-time location tracking systems. However, whenever you enter a destination on Uber or Lyft, a few seconds later, you see your current location, the destination, and a route, along with estimates of arrival times. From where did your ride-hailing app get this data?
The answer is that your smartphone apps access data through APIs (application programming interface).
Your weather app uses an API to get weather data from one of the many online weather services.
Your ride-hailing app uses Google Maps API (or a similar service) to access real-time tracking information.
APIs are software developed for software developers. Software developers need high-quality API documentation to use APIs and extract the maximum benefit.
This article will go over the best way to write API documentation.
Let’s get right into it.
What are the Types of API Documentation?
There are three types of API documentation: reference, tutorial, and conceptual.
API Reference
Reference documentation provides information about the structure, parameters, and return values for each function or method in an API. This is the most important type of API documentation, as developers spend most of their time on reference documentation.
Tutorials
Tutorials provide step-by-step guides for using APIs to accomplish specific tasks. They are helpful if your users want to learn about specific use cases. Tutorials contain detailed instructions on the use of specific function calls and parameters.
Conceptual
In contrast to tutorials that provide specifics, conceptual documentation provides higher-level information, such as how to use APIs to build applications and integrate APIs into a single application.
How to Write API Documentation: A Step-by-Step Guide
Writing great API documentation can be challenging, but you can do it well if you follow best practices. A good understanding of APIs also helps. It’s ideal if you have some knowledge of programming languages, such as PHP, Java, and Python, along with some technical writing experience.
Furthermore, good communication skills are essential for effective coordination between team members and developers.
You can check out API technical documentation from major companies like Microsoft to better understand the format and content.
To write excellent API documentation, use templates, use the correct API documentation tools, and follow a step-by-step process.
You can start following the steps described below when you’ve set yourself up with the first two.
Gain An In-Depth Understanding of How the API Works
Before you can create the documentation, it is essential that you first understand how the API works. You can either look at the source code to understand the API or work with the product owner, developers, and engineers to develop the required understanding.
Make a Plan for Your API Documentation
The next step is to plan out your API documentation process. If you don’t develop a complete plan and set up a schedule, there’s a good chance that you’ll either miss out on key points or miss your deadlines.
Before working on the API documentation, you must understand your audience well. Understanding your audience and their needs is crucial to planning documentation. That’s because it will help you decide on your documentation’s structure, language, and overall design.
Furthermore, it is best to learn about the API itself, whether it’s a web API, payment API, or an API with a different function. You must also consider what API documentation tools you will use, such as Postman, SwaggerHub, or apiDoc. You can also consider using online sources and tutorials from sites like GitHub.
To ensure the API works for people who use the API documentation, you’ll have to look at the API blueprint, API design, and API key.
Understanding these essential concepts and developing API documentation with the user experience in mind will help you plan well.
Include Critical Sections
Each API document needs to have some fundamental sections. These sections improve the document’s usability and enhance the developer experience.
According to Smartbear, the following are some of the most important sections for API documentation.
- Examples: It’s no wonder that examples are the most essential thing developers look for in API documentation. After all, developers need to use the API; examples show them how. Examples are included as pieces of code. You can also include a mock API for developers to test and use by making actual calls. You can share the mock APIs via a URL or on GitHub.
- Product overview: The product overview is an essential section as it is relevant for technical users and for decision-makers who can use the information in this section to decide whether or not to buy the API. Documentation often tends to focus on technical details, and the API’s overall business goals and purpose are ignored.
- The overview section includes what you can do with the product, the market needs or pain points it solves, some examples of its use, its requirements, who the product or other features are for, and other introductory information.
- Getting Started Guide: API docs are complex technical documents that some users find overwhelming. A getting started section can make it easier for inexperienced and experienced users to navigate the documentation and find what they want. This section helps show users how to use a framework, API, or some other system to get the simplest and easiest result so they get an end-to-end sense of how it works.
- Authentication: Authentication and authorization are essential API functions. APIs don’t work without them. Since developers can’t use the API without knowledge of API keys, this section needs to appear right after the getting started section. In this section, you must explain the necessary information, such as how to get API keys, authenticate requests, error messages related to invalid authentication, sensitivity around authentication information, and token expiration times.
- You don’t need to explain the authentication in detail to outside users. This is because keeping the internal details of your authentication process confidential prevents hackers from obtaining unauthorized access. It is also essential to explain the use of public and private keys, where each key is used, and emphasize that private keys are confidential (not shared). Include related information in this section if you use different license tiers to provide other access to the API calls.
- Status codes and error messages: Everyone is bound to get some error messages when using an API. Therefore, the user must understand each error message, its reason, and potential solutions. This section is helpful in first-use cases where someone is using an API for the first time. It’s a good idea to list status codes and error messages on a separate page as it allows you to describe each code in detail without crowding the other documentation. You will need to ask the API developers for a list of all your API’s status codes and error messages. Status codes and error messages can be helpful when it comes to troubleshooting.
- HTTP requests: Including relevant information about web requests in your API documentation is essential. This is because even though developers know how to send web requests in their preferred programming languages, they might not be familiar with the language used to create requests in the API.
Stay Consistent and Avoid Jargon
When you’ve figured out the sections and start writing the API document, you must ensure consistency. You use the same terminology, formatting, and reference points throughout the document.
Remember that not all users of API docs have experience with APIs. So it’s a good idea to write for the entry-level. That way, your documentation will benefit users with different levels of experience.
Ensure all content is uniform in all aspects, including formatting and language. The best way to ensure consistency is to proofread each section after writing it and then proofread the entire document once complete. If you notice any problematic areas that need to be understood and read, either edit or remove them altogether.
Furthermore, it’s important to avoid jargon. It’s best to use standard terminology so that everyone can understand the terms. If you can, avoid using technical jargon unless it is necessary.
You’re already doing a great job with technical writing if you can convert all technical jargon into understandable words and sentences. The idea is to write something that resonates with the user and helps them understand complex aspects.
It’s best not to assume that everyone who reads the API document understands all about APIs. Therefore, the language should be consistent and straightforward so that even first-time users can grasp all the concepts.
Use Interactive Examples
When you write a block of text, there’s a good chance people will avoid reading all of it. You must keep your readers engaged; the best way is by including interactive code samples and demos.
One way of teaching and learning concepts is in isolation. However, this method is an ineffective method of teaching and learning. One of the significant benefits of using examples is that they provide a context that links multiple concepts and enhances learning. Examples based on real-world API applications enhance learning by bringing in variables that API developers must deal with daily.
Interactive examples will help the reader comprehend the API documentation because they will apply what they’re reading in real-time. It will also reduce the learning curve of the API in the long run. Furthermore, it can help users understand any new features that pop out.
You can also include helpful resources like SDKs and libraries in the API documentation. The extra resources and information will help the users understand the API better and use it effectively.
Maintain the API Documentation
While good documentation is crucial for API success, maintaining API docs is also critical.
It’s crucial to ensure all your documents remain accurate and up-to-date. Obsolete API documentation will lead to frustrated users, reduced retention, and increased support costs as developers repeatedly turn to your teams for help.
It’s not hard to maintain your API documentation; you can do the following to make sure it stays updated:
- If any new features have been added to the API, ensure all relevant information appears in the documents. A good practice is to release updated API documentation with each new API release.
- Update descriptions for any features that are added or removed. If a feature is removed, mention it in the document and the reasoning behind it.
- As a writer, feedback is important to improve the quality of your API documentation. You may have missed out on some things or were unclear; therefore, it’s best to use the feedback to improve.
API Documentation Best Practices
Here are some best practices that will improve the developer experience for your API documentation.
Use Simple Language
It is easy to create API documentation with document generation tools. However, such auto-generated documentation lacks good explanations that only a good developer or technical writer can provide.
Therefore, create API documentation written in simple language, making it easy for developers to use and benefit from.
Make it Accurate, Compact, and Easy to Find
API docs that are disorganized, inaccurate, too long, or difficult to locate will not be used. So, make API docs easy to find and use.
Make it Available for Everyone
Many customers prefer to understand what your API does before buying it. Your API documentation can help them decide.
Limiting access to registered users is terrible marketing and prevents potential clients from learning about your products and services.
API Documentation Tools
Using an API documentation tool can provide many benefits. Tools help reduce the time it takes developers and technical writers to write and maintain API documentation by automating or simplifying some tasks.
Some of the features that API documentation tools support include automatic updates to documentation based on changes to source code, version control, collaboration, and customization options.
Here are some tools used for writing API docs.
Postman
Postman is an API platform for developers to design, build, test, and iterate their APIs.
You can use Postman’s API documentation tool to generate machine-readable documentation for your API and keep it current.
Postman pulls sample requests, headers, code snippets, and more to populate the documentation with dynamic examples and machine-readable instructions. It also updates documentation when you make changes to your collection.
Swaggerhub
SwaggerHub is an integrated API design and documentation platform built for teams to drive consistency and discipline across the API development workflow.
Supported features include smart error feedback and syntax auto-completion, embedded API design rules that reinforce standards in real-time, and real-time commenting and issue tracking.
Redocly
Redocly is an open-source tool that generates API documentation from OpenAPI specifications.
It supports version control, collaboration, user roles, try-it authentication, and other security features. A unique feature is preview functionality: you can preview every branch or pull request to ensure your changes are reviewed and discussed before pushing to production.
Who Writes API Documentation?
Writing API documentation requires technical skills and an understanding of how APIs work. It is a collaborative process between developers, technical writers, and other stakeholders.
Developers
API docs are written by the people with the best understanding of the APIs, i.e., software developers. Even though developers have the best technical knowledge of APIs, they might not have the best writing skills or give the highest priority to writing documentation.
This is where technical writers come in.
Technical Writers
The job of technical writers is to translate complex technical subject matter into easy-to-understand explanations.
Even though programming experience is not essential, technical writers with programming experience write the best API documentation. Technical writers collaborate with developers and other stakeholders to create API documentation.
Other Stakeholders
Sometimes, organizations don’t have dedicated technical writers, and the responsibility for writing API documentation falls on product owners, content writers, or even the startup founder. The essential skills required for the role include writing and technical knowledge.
Wrap Up
‘API economy’ is the term used to denote the new way of distributing software and data that relies on APIs. And the size of the API economy keeps growing:
- According to the 19th Developer Economics Survey, 90% of software developers use APIs.
- Developers spend 30% of their time coding APIs.
- The value of the API management market will reach $5.1 Billion by 2023.
- 83% of all Internet traffic belongs to API-based services.
In other words, APIs make the world go round.
Whether a software developer or technical writer, knowing how to create excellent API documentation will help you in your job and career. Following the steps outlined in this article can help you create great API documentation and guide others.
FAQs
Here are the most frequently asked questions about API documentation.
What is an API documentation template, and why is it important?
An API documentation template provides a standardized structure for documenting existing APIs, ensuring consistency and clarity. It helps developers quickly understand how to interact with an API by outlining endpoints, request methods, authentication details, and response formats. Using a template streamlines the documentation process, making it easier to maintain and scale.
How does the API documentation workflow improve efficiency?
An API workflow establishes a structured process for creating, reviewing, and updating API documentation. It ensures that existing documentation is accurate, up-to-date, and aligned with development changes. A well-defined workflow integrates seamlessly with API development, allowing teams to automate documentation generation and validation, reducing errors and improving overall efficiency.
Why is interactive documentation beneficial for developers?
Interactive documentation enhances the developer experience by allowing users to explore and test API endpoints in real-time. It often includes live request simulations, code samples, and dynamic responses, enabling developers to understand and implement the API more effectively. This approach reduces onboarding time and minimizes errors in API integration.
What are the key components of REST API documentation?
REST API documentation should clearly define endpoints, HTTP methods, request parameters, authentication requirements, and response structures. It should also include examples of successful and error responses. Well-structured REST API documentation ensures developers can efficiently integrate and troubleshoot API interactions.
How can interactive documentation enhance the API documentation workflow?
Combining interactive documentation with a well-structured API documentation workflow improves accessibility and usability. Interactive elements allow developers to experiment with API endpoints while maintaining a clear and organized documentation process. This integration reduces misunderstandings, accelerates development, and enhances overall API adoption.
If you are new to technical writing, we recommend taking our Technical Writing Certification Course. You will learn the fundamentals of being a technical writer, how to dominate technical writer interviews, and how to stand out as a technical writing candidate.
