This package provides the TypeSpec emitter to produce OpenAPI 3.0 output from TypeSpec source.

In your typespec project root

npm install @typespec/openapi3

1. Via the command line

tsp compile . --emit @typespec/openapi3

2. Via the config

Add the following to the tspconfig.yaml file.

emitters:
  @typespec/openapi3: true

For configuration see options

import "@typespec/openapi3";

using OpenAPI;

// Using `using`
@useRef("common.json#/components/schemas/Foo")
model Foo {}

// Using fully qualified names
@OpenAPI.oneOf
union MyUnion {
  cat: Cat,
  dog: Dog,
}

• @useRef
• @oneOf

Syntax:

@useRef(urlString)

@useRef

@useRef is used to replace the TypeSpec model type in emitter output with a pre-existing named OpenAPI schema.

Syntax:

@oneOf()

@oneOfemits oneOf keyword for a union type in the resulting OpenAPI 3.0 specification. It indicates that the value of union type can only contain exactly one of the subschemas.

@oneOf can only be applied to a union types.

Emitter options can be configured via the tspconfig.yaml configuration:

emitters:
  '@typespec/openapi3':
    <optionName>: <value>


# For example
emitters:
  '@typespec/openapi3':
    outputFile: my-custom-openapi.json

or via the command line with

--option "@typespec/openapi3.<optionName>=<value>"

# For example
--option "@typespec/openapi3.output-file=my-custom-openapi.json"

Configure the name of the swagger output file relative to the compiler output-path.

Set the newline character for emitting files. Can be either:

• lf(Default)
• crlf

Only include types referenced via an operation.

• TypeSpec Getting Started
• TypeSpec Website
• TypeSpec for the OpenAPI Developer