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Step 2: The info object (OpenAPI tutorial)

Last updated: Jun 25, 2020

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The info object contains basic information about your API, including the title, a description, version, link to the license, link to the terms of service, and contact information. Many of the properties are optional.

Sample info object

Here’s an example of the info object and its properties. (The openapi object and the empty paths object are commented out to maintain the focus on the info object.)

# openapi: 3.0.2
  title: "OpenWeatherMap API"
  description: "Get the current weather, daily forecast for 16 days, and a three-hour-interval forecast for 5 days for your city. Helpful stats, graphics, and this day in history charts are available for your reference. Interactive maps show precipitation, clouds, pressure, wind around your location stations. Data is available in JSON, XML, or HTML format. **Note**: This sample Swagger file covers the `current` endpoint only from the OpenWeatherMap API. <br/><br/> **Note**: All parameters are optional, but you must select at least one parameter. Calling the API by city ID (using the `id` parameter) will provide the most precise location results."
  version: "2.5"
  termsOfService: ""
    name: "OpenWeatherMap API"
    url: ""
    email: "[email protected]"
    name: "CC Attribution-ShareAlike 4.0 (CC BY-SA 4.0)"
    url: ""
# paths: {}

If you get stuck, see the sample OpenAPI spec here for the fully working sample. This will help you spot and troubleshoot indentation or other errors.

Description properties and Markdown

Note that in any description property, you can use CommonMark Markdown, which is much more precise, unambiguous, and robust than the original Markdown.

For example, CommonMark markdown offers some backslash escapes, and it specifies exactly how many spaces you need in lists and other punctuation. You can also break to new lines with \n and escape problematic characters like quotation marks or colons with a backslash.

As you write content in description properties, note that colons are problematic in YAML because they signify new levels. Either enclose the description value in quotation marks or escape colons with a backslash. (If you enclose the values in quotation marks, syntax highlighters in text editors can display better color coding between the properties and values.)

Update your file in Swagger Editor

To update the spec file in Swagger Editor:

  1. Paste the code from the preceding section (“Sample info object”) containing the info object into the Swagger Editor.
  2. Uncomment the openapi and paths objects (remove the “#”). The display looks as follows:

    openapi, info, and empty paths object in Swagger Editor
    openapi, info, and empty paths object in Swagger Editor

    In the Swagger UI display, the info object’s information appears below the title.

In the description property, in addition to describing your overall API, you might want to provide some basic instructions to users on how to use Swagger UI. If there’s a test account they should use, you can provide the information they need in this space.

About Tom Johnson

Tom Johnson

I'm an API technical writer based in the Seattle area. On this blog, I write about topics related to technical writing and communication — such as software documentation, API documentation, AI, information architecture, content strategy, writing processes, plain language, tech comm careers, and more. Check out my API documentation course if you're looking for more info about documenting APIs. Or see my posts on AI and AI course section for more on the latest in AI and tech comm.

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