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3.6.7 • Public • Published


OpenAPI / Swagger / AsyncAPI / Semoasa definition to Slate / Shins compatible markdown

Build Tested on Tested on Mermade OpenAPIs Known Vulnerabilities

Widdershins adverb:

  • In a direction contrary to the sun's course;
  • anticlockwise;
  • helping you produce static documentation from your OpenAPI 3.0 / Swagger 2.0 / AsyncAPI 1.x / Semoasa 0.1.0 definition

Widdershins screenshot


  • As of v3.0.0 Widdershins no longer expands the definition of OpenAPI body parameters / requestBodies by default, unless they have an inline schema. You can restore the old behaviour by using the --expandBody option.
  • You may limit the depth of schema examples using the --maxDepth option. The default is 10.
  • To omit schemas entirely, please copy and customise the template.
  • As of v3.1.0 Widdershins includes a generated Authorization header in OpenAPI code samples. If you wish to omit this, see here.
  • If you are using Node.js 6 or lower, please specify the --harmony flag.

To install

  • Clone the git repository, or
  • npm install [-g] widdershins


Command-line use looks like this:

node widdershins [options] {input-file|url} [[-o] output markdown]

For example:

node widdershins --search false --language_tabs 'ruby:Ruby' 'python:Python' --summary defs/petstore3.json -o


CLI parameter name JavaScript parameter name Type Default value Description
--customApiKeyValue options.customApiKeyValue string ApiKey Set a custom API key value
--expandBody options.expandBody boolean false Expand the requestBody parameter to show all properties in the request body
--headings options.headings integer 2 The number of headings to show in the table of contents. Currently supported only by Shins, not by Slate, which lacks this feature.
--omitBody options.omitBody boolean false Omit the top-level fake body parameter object
--resolve options.resolve boolean false Resolve external $refs, using the source parameter or the input file as the base location
--shallowSchemas options.shallowSchemas boolean false Don't expand schemas past $refs
N/A options.source string The absolute location or URL of the source file to use as the base to resolve relative references ($refs) from; required if options.resolve is set to true. For CLI commands, Widdershins uses the input file as the base for the $refs.
--summary options.tocSummary boolean false Use the operation summary as the TOC entry instead of the ID
--verbose options.verbose boolean false Increase verbosity
-h, --help boolean false Show help
--version options.version boolean false Show version number
-c, --code options.codeSamples boolean false Turn generic code samples off
--httpsnippet options.httpsnippet boolean false Use httpsnippet to generate code samples
-d, --discovery options.discovery boolean false Include WebAPI discovery data
-e, --environment options.environment string None Load config/override options from file
-i, --includes options.includes string None List of files to include, comma separated
-l, --lang options.lang boolean false Automatically generate list of languages for code samples
--language_tabs options.language_tabs string (Differs for each input type) List of language tabs for code samples using language[:label[:client]] format
-m, --maxDepth options.maxDepth integer 10 Maximum depth for schema examples
-o, --outfile options.outfile string (If left blank, output to stdout) File to write output markdown to
-r, --raw options.raw boolean false Output raw schemas not example values
-s, --search boolean true Whether to enable search or not
-t, --theme options.theme string darkula Syntax-highlighter theme to use
-u, --user_templates options.user_templates string None Directory to load override templates from
-x, --experimental options.experimental boolean For backwards compatibility only, ignored
-y, --yaml options.yaml boolean false Display JSON schemas in YAML format
options.templateCallback function None A function that is called before and after each template (JavaScript code only)

In Node.JS code, create an options object and pass it to the Widdershins convert function, as in this example:

const converter = require('widdershins');
let options = {}; // defaults shown
options.codeSamples = true;
options.httpsnippet = false;
//options.language_tabs = [];
//options.language_clients = [];
//options.loadedFrom = sourceUrl; // only needed if input document is relative
//options.user_templates = './user_templates';
options.templateCallback = function(templateName,stage,data) { return data };
options.theme = 'darkula'; = true;
options.sample = true; // set false by --raw
options.discovery = false;
options.includes = [];
options.shallowSchemas = false;
options.tocSummary = false;
options.headings = 2;
options.yaml = false;
//options.resolve = false;
//options.source = sourceUrl; // if resolve is true, must be set to full path or URL of the input document
  // str contains the converted markdown

To only include a subset of the pre-defined language-tabs, or to rename their display-names, you can override the options.language_tabs:

options.language_tabs = [{ 'go': 'Go' }, { 'http': 'HTTP' }, { 'javascript': 'JavaScript' }, { 'javascript--nodejs': 'Node.JS' }, { 'python': 'Python' }, { 'ruby': 'Ruby' }];

The --environment option specifies a JSON or YAML-formatted options object, for example:

  "language_tabs": [{ "go": "Go" }, { "http": "HTTP" }, { "javascript": "JavaScript" }, { "javascript--nodejs": "Node.JS" }, { "python": "Python" }, { "ruby": "Ruby" }],
  "verbose": true,
  "tagGroups": [
      "title": "Companies",
      "tags": ["companies"]
      "title": "Billing",
      "tags": ["invoice-create", "invoice-close", "invoice-delete"]

You can also use the environment file to group OAS/Swagger tagged paths together to create a more elegant table of contents, and overall page structure.

If you need to support a version of Slate <v1.5.0 (or a renderer which also doesn't support display-names for language-tabs, such as node-slate, slate-node or whiteboard), you can use the --environment option with the included whiteboard_env.json file to simply achieve this.

If you are using the httpsnippet option to generate code samples, you can specify the client library used to perform the requests for each language by overriding the options.language_clients:

options.language_clients = [{ 'shell': 'curl' }, { 'node': 'request' }, { 'java': 'unirest' }];

To see the list of languages and clients supported by httpsnippet, click here.

The loadedFrom option is only needed where the OpenAPI / Swagger definition does not specify a host, and (as per the OpenAPI specification) the API endpoint is deemed to be based on the source URL the definition was loaded from.

Note that the list of included files is simply passed into the header of the markdown file, they are actually included by Slate or the alternative you use.

To see the list of highlight-js syntax highlighting themes, click here. WebAPI discovery data is included if the discovery option above is set true. See the W3C WebAPI Discovery Community Group for more information.

Language tabs

Widdershins supports the x-code-samples vendor-extension to completely customise your documentation. Alternatively, you can edit the default code-samples in the templates sub-directory, or override them using the user_templates option to specify a directory containing your templates.

Widdershins supports the use of multiple language tabs with the same language (i.e. plain Javascript and Node.Js). To use this support you must be using Slate (or one of its ports compatible with) version 1.5.0 or higher. Shins versions track Slate version numbers.

Template parameters

Templates are compiled with doT.js.

Templates have access to a data object with a range of properties based on the document context.

If you specify an options.templateCallback function, it will be called before and after each template, with three parameters, the template name, the stage, ('pre' or 'post') and the current data object. You can mutate the data object in any way you see fit, as long as you return it. Content in the data.append property will be appended to the current output stream.

User templates

To override a .dot template, you need to copy over the child .def partials as well.

To override a .def partial, you need to copy over the parent .dot template as well. For OpenAPI 3 this will be except for parameters, responses and callbacks, which are children of the template.

This means it is usually easiest to copy all .dot and .def files to your user templates directory. A visual diff tool which can run across two directories (such as Meld or WinMerge) may be useful in bringing in changes from Widdershins updates.


To run a test-suite:

node testRunner {path-to-APIs}

The test harness currently expects .yaml or .json files and has been tested against

Comparison between this and other OpenAPI / Swagger to Slate tools

Blog posting by the author of Widdershins.


Widdershins in the wild

Please feel free to add a link to your API documentation here.

Widdershins and Shins

  • Widdershins works well with Slate, but for a solely Node.js-based experience, why not try the Shins port?


npm i widdershins

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