# The thoroughness of Tom Johnson's free Documenting API's course on OpenAPI 3.0 and Swagger UI

DevFeed: [The thoroughness of Tom Johnson's free Documenting API's course on OpenAPI 3.0 and Swagger UI](<https://devfeed.tech/articles/the-thoroughness-of-tom-johnson-s-free-documenting-api-s-course-on-openapi-3-0-and-swagger-ui-22428.md>)

Original publisher: [Read original article](<https://www.tjmaher.com/2026/09/the-thoroughness-of-tom-johnsons-free.html>)

Author: T.J. Maher (noreply@blogger.com)

Published: 2026-09-09T21:17:32Z

Content type: article

Language: en

Sources: [T.J. Maher](<https://devfeed.tech/sources/t-j-maher.md>)

Topics: [OpenAPI Specification](<https://devfeed.tech/topics/openapi.md>), [Documentation](<https://devfeed.tech/topics/documentation.md>), [REST API](<https://devfeed.tech/topics/rest-api.md>), [Swagger](<https://devfeed.tech/topics/swagger.md>), [Testing](<https://devfeed.tech/topics/testing.md>), [Postman](<https://devfeed.tech/topics/postman.md>), [JavaScript](<https://devfeed.tech/topics/javascript.md>), [JSON](<https://devfeed.tech/topics/json.md>), [Authentication](<https://devfeed.tech/topics/authentication.md>), [cURL](<https://devfeed.tech/topics/curl.md>), [Chrome](<https://devfeed.tech/topics/chrome.md>), [Open Source](<https://devfeed.tech/topics/open-source.md>)

Tags: [api](<https://devfeed.tech/tags/api.md>), [api-documentation](<https://devfeed.tech/tags/api-documentation.md>), [authentication](<https://devfeed.tech/tags/authentication.md>), [chrome](<https://devfeed.tech/tags/chrome.md>), [chrome-extension](<https://devfeed.tech/tags/chrome-extension.md>), [curl](<https://devfeed.tech/tags/curl.md>), [documentation](<https://devfeed.tech/tags/documentation.md>), [github](<https://devfeed.tech/tags/github.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [json](<https://devfeed.tech/tags/json.md>), [openapi](<https://devfeed.tech/tags/openapi.md>), [pdf](<https://devfeed.tech/tags/pdf.md>), [postman](<https://devfeed.tech/tags/postman.md>), [rest-api](<https://devfeed.tech/tags/rest-api.md>), [swagger](<https://devfeed.tech/tags/swagger.md>), [testing](<https://devfeed.tech/tags/testing.md>)

## AI overview

The article reviews Tom Johnson's free "Documenting APIs: A guide for technical writers and engineers" course. It describes the course's 17 chapters, practical API-learning exercises, coverage of REST APIs, OpenAPI, Swagger UI, testing and publishing API documentation, and a PDF edition exceeding 900 pages.

## Source excerpt

While researching information for my job about the Swagger UI and how it can be used for testing, I came across this free course, called Documenting APIs: A guide for technical writers and engineers at https://idratherbewriting.com/learnapidoc/docapis_overview.html written by Tom Johnson, a technical writer based in Seattle who works for Google. The course looks intense, containing 17 chapters talking about Introduction to REST APIs, using APIs like a developer, Documenting API endpoints, the Open API spec, Testing API docs, Publishing API docs, and more. From the Course Introduction: "You'll first learn about API documentation by using a simple weather API to put a weather forecast on your site. [...] As you use the API, you'll learn about endpoints, parameters, data types, authentication, curl, JSON, the command line, Chrome's Developer Console, JavaScript, and more. 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. Immersion in real scenarios makes these tools and technologies more meaningful. "We'll then transition into standards, tools, and specifications for REST APIs. You'll learn about the required sections in API documentation, analyze examples of REST API documentation from various companies, learn how to join an open-source project to get experience, and more. "[...] We'll also dive into specifications such as the OpenAPI specification and Swagger UI (which provides tooling for the OpenAPI specification). Additionally, you'll learn how to document native library APIs and generate Javadoc". Tom Johnson offers a PDF version of this free course... over 900 pages, with more always being added. It also offers many workshop-like activities you could put in an actual itinerary. You would need for the course: Chrome, since it provides "a Javascript Console that works well for inspecting JSON", the JSON Formatter Chrome extension, Postman, a GitHub acco