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Widdershins

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What Widdershins is

Widdershins converts API definitions into documentation output for a renderer in an API documentation pipeline. It accepts OpenAPI 3.x and 2.0, API Blueprint, AsyncAPI, and Semoasa inputs. It can produce Markdown compatible with Slate and ReSlate, HTML directly, or ReSpec format; integrations described by the project include Slate, ReSlate, Shins, and ReSpec. Code samples can be customized, including language tabs, and httpsnippet can generate samples. Users can adapt output by editing or overriding the included templates. Widdershins can be installed globally with npm install -g widdershins or from a cloned repository using npm i. Node.js applications can call its convert function, which returns a Promise. The project is free, open-source, and MIT-licensed. Schema examples have a default maximum depth of 10, and referenced request body schemas are not expanded by default unless they include an inline schema. OpenAPI code samples can generate Authorization headers, and an option allows customization of the API key value.

Who it suits

Widdershins suits developers building API documentation pipelines who need to convert supported definitions for a renderer. It can also suit teams that want to customize templates and code samples.

What it does well

  • Accepts OpenAPI, API Blueprint, AsyncAPI, and Semoasa inputs.
  • Produces Markdown, HTML, or ReSpec format.
  • Templates and code samples are customizable.
  • Free and MIT-licensed.

What to know first

  • Schema examples default to a maximum depth of 10.
  • Referenced request body schemas are not expanded by default without an inline schema.

Limits

Schema examples default to a maximum depth of 10. Referenced request body schemas are not expanded by default unless they include an inline schema.

Plans

PlanBilled and limitsPrice
WiddershinsOpen source MIT-licensed software · install via npm or clone the repositoryFree

As github.com lists them, read 4 Oct 2026. The maker's own page has the final word.

Getting started

  1. Install globally with npm install -g widdershins, or clone the repository and run npm i.
  2. Provide an OpenAPI, API Blueprint, AsyncAPI, or Semoasa definition.
  3. Convert the definition to Markdown, HTML, or ReSpec format.
  4. Use the generated content with a renderer such as Slate, ReSlate, Shins, or ReSpec.
  5. For Node.js use, call the convert function, which returns a Promise.

Verdict

Widdershins offers several API definition inputs and renderer-oriented outputs, with templates and samples users can adapt. Its default schema expansion behavior may matter when preparing documentation.

Questions

How much does Widdershins cost?

It is free and open source under the MIT license.

Which API definition formats can it convert?

It supports OpenAPI 3.x and 2.0, API Blueprint, AsyncAPI, and Semoasa.

What output formats does it provide?

It produces Markdown, including Markdown compatible with Slate and ReSlate, and can also output HTML directly or use ReSpec format.

How can I install it?

Install it globally with npm install -g widdershins, or clone the repository and run npm i.

Can Node.js applications use it?

Yes. Node.js applications can call its convert function, which returns a Promise.

What are the schema limits?

Schema examples default to a maximum depth of 10. Referenced request body schemas are not expanded by default unless they have an inline schema.

Facts from Widdershins's own pages

API use
Widdershins can be called from Node.js using its convert function, which returns a Promise. · github.com, 4 Oct 2026
Code samples
It supports customizable code samples, including language tabs, and can use httpsnippet to generate samples. · github.com, 4 Oct 2026
Input formats
The project describes support for OpenAPI 3.x, OpenAPI 2.0, API Blueprint, AsyncAPI, and Semoasa inputs. · github.com, 4 Oct 2026
Install
The project can be installed globally with npm install -g widdershins or installed by cloning the repository and running npm i. · github.com, 4 Oct 2026
Integrations
The README describes using Widdershins with Slate, ReSlate, Shins, and ReSpec renderers. · github.com, 4 Oct 2026
License
The repository identifies its license as MIT. · github.com, 4 Oct 2026
Limits
Schema examples default to a maximum depth of 10, and referenced request body schemas are not expanded by default unless they have an inline schema. · github.com, 4 Oct 2026
Output formats
Widdershins can produce Markdown and can also output HTML directly or use ReSpec format. · github.com, 4 Oct 2026
Pipeline
It is intended as a stage in an API documentation pipeline, converting API definitions for a renderer. · github.com, 4 Oct 2026
Purpose
Widdershins converts OpenAPI, Swagger, AsyncAPI, and Semoasa definitions into Markdown compatible with Slate and ReSlate. · github.com, 4 Oct 2026
Security
The README documents generated Authorization headers in OpenAPI code samples and provides an option to customize the API key value. · github.com, 4 Oct 2026
Templates
Users can customize output by editing or overriding the included templates. · github.com, 4 Oct 2026

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