Documenting APIs: A guide for technical writers
In this course on writing documentation for REST APIs, instead of just talking about abstract concepts, I contextualize REST APIs with a direct, hands-on approach.
You’ll learn about API documentation in the context of using some simple weather APIs to put a weather forecast on your site.
The idea is that rather than learning about these concepts independent of any context, you learn them by immersing yourself in a real scenario while using an API. This makes these tools and technologies more meaningful.
- About REST APIs
- From practice to documentation
- Course organization
- No programming skills required
- What you’ll need
- Will this course help you get a job in API documentation?
- Video recordings
- Stay updated
About REST APIs
In a nutshell, REST APIs (which are a type of web API) involve requests and responses, not too unlike visiting a web page. You make a request to a resource stored on a server, and the server responds with the requested information. The protocol used to transport the data is HTTP. “REST” stands for representational state transfer.
I dive more into the principles of REST in What is a REST API? In your REST API documentation, you describe the various endpoints available, their methods, parameters, and other details, and you also document sample responses from the endpoints.
From practice to documentation
In this course, after you practice using an API like a developer, you’ll then shift perspectives and “become a technical writer” tasked with documenting a new endpoint that has been added to an API.
As a technical writer, you’ll tackle each element of a reference topic in REST API documentation:
Diving into these sections will give you a solid understanding of how to document REST APIs. You’ll also learn how to document the non-reference sections for an API, such as the getting started, status and error codes, and request authorization sections.
Finally, you’ll dive into different ways to publish REST API documentation, exploring tools and specifications such as GitHub, Jekyll, and other Docs-as-code approaches. You’ll learn how to leverage templates, build interactive API consoles so users can try out requests and see responses, and learn how to manage your content through version control.
I also dive into specifications such as the OpenAPI specification and Swagger, which provides tooling for the OpenAPI specification. Additionally, I included a section on documenting native library APIs and generating Javadoc. Throughout it all, I put these tools in a real, applicable context with examples and demos.
This course is organized into the following sections:
- Introduction to REST APIs
- Using a REST API like a developer
- Documenting endpoints
- Testing your API documentation
- Documenting non-reference sections
- Publishing your API documentation
- OpenAPI specification and Swagger
- Documenting native library APIs
- Getting a job in API documentation
- Resources and glossary
You don’t have to read the sections in order — feel free to skip around as you prefer. But some of the earlier sections (such as the section on Using a REST API like a developer, and the section on documenting endpoints) follow a somewhat sequential order with the same weather API scenario.
Because the purpose of the course is to help you learn, there are many activities that require hands-on coding and other exercises. Along with the learning activities, there are also conceptual deep dives, but the focus is always on learning by doing. Where there are hands-on activities, I include an activity graphic like this:
I refer to the content here as a “course” instead of a book or a website, primarily because I include a lot of exercises throughout in each section, and I find that people who want to learn API documentation prefer a more hands-on “course” experience. However, this content is just as much a book or website as it is a course.
No programming skills required
If you do have some familiarity with programming concepts, you might speed through some of the sections and jump ahead to the topics you want to learn more about. This course assumes you’re a beginner, though.
What you’ll need
Here are a few things you’ll need to do the exercises in this course:
- Text editor. (Atom editor or Sublime Text are good options, and they work on both Mac and Windows.
- Postman. Postman is an app that allows you to make requests and see responses through a GUI client.
- curl. curl is essential for making requests to endpoints from the command line. Mac computers already have curl installed. Windows users should follow the instructions for installing curl here.
- Git. Git is a version control tool developers often use to collaborate on code. See Set Up Git for more details.
- GitHub account. GitHub will be used for various activities and is commonly used as an authentication service for developer tools. If you don’t already have a GitHub account, sign up for one.
- Stoplight App. Stoplight provides visual modeling tools for working with the OpenAPI specification. Create a Stoplight account and download the Desktop app here.
Will this course help you get a job in API documentation?
The most common reason people take this course is to transition to an API documentation. This course will help you make that transition, but you can’t just passively read through the content. You’ve got to do all the activities outlined in each section. These activities are key to building experience and credibility with a portfolio. These in-depth activities are identified with the word “Activity” in the topic title. There is usually one main activity for each section:
- Activity: Find an Open Source Project
- Activity: Critique or create an API reference topic
- Activity: Test the docs in your Open Source project
- Activity: Manage content in a GitHub wiki
- Activity: Create an OpenAPI specification document
- Activity: Create your own Swagger UI display
- Activity: Generate a Javadoc from a sample project
For video recordings of this course, see the Recorded Video Presentations.
I have various slides that cover different sections of this course. See the following:
- Intro to API documentation
- Non-reference content in API docs
- OpenAPI and Swagger
- Publishing API documentation
(By the way, these slides are all hosted on GitHub at https://github.com/tomjoht/. I use RevealJS for slides, which lets me create the slide content in HTML.)
If you’re following this course, you most likely want to learn more about APIs. I publish regular articles that talk about APIs and strategies for documenting them. You can stay updated about these posts by subscribing to my free newsletter at https://tinyletter.com/tomjoht.
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If you would like to contribute back to say thank you for the API documentation course, click the Donate button below. Alternatively, to contribute content, such as a tutorial or a new section, contact me with your ideas. You can also submit a pull request in the GitHub repo to make your contribution. Even if you want to just fix a typo or add a sentence here and there, it's always welcome.
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