This is an example of linting an OpenAPI 3 document with Spectral and Node.js

test-oas3.js

// This example is designed to be using Spectral (https://github.com/stoplightio/spectral#installation) and Node.js (https://nodejs.org/)

// If you have both installed locally, it can be run with the command: node test-oas3.js

const { Spectral } = require('@stoplight/spectral');
const { oas3Functions, oas3Rules } = require('@stoplight/spectral/rulesets/oas3');

// an OAS 3 document
var myOAS = {
	"openapi": "3.0.0",
	"info": {
		"version": "1.0.0",
		"title": "Swagger Petstore",
		"license": {
			"name": "MIT"
		}
	},
	"servers": [
		{
			"url": "http://petstore.swagger.io/v1"
		}
	],
	"paths": {
		"/pets": {
			"get": {
				"summary": "List all pets",
				"operationId": "listPets",
				"tags": [
					"pets"
				],
				"parameters": [
					{
						"name": "limit",
						"in": "query",
						"description": "How many items to return at one time (max 100)",
						"required": false,
						"schema": {
							"type": "integer",
							"format": "int32"
						}
					}
				],
				"responses": {
					"200": {
						"description": "A paged array of pets",
						"headers": {
							"x-next": {
								"description": "A link to the next page of responses",
								"schema": {
									"type": "string"
								}
							}
						},
						"content": {
							"application/json": {
								"schema": {
									"$ref": "#/components/schemas/Pets"
								}
							}
						}
					},
					"default": {
						"description": "unexpected error",
						"content": {
							"application/json": {
								"schema": {
									"$ref": "#/components/schemas/Error"
								}
							}
						}
					}
				}
			},
			"post": {
				"summary": "Create a pet",
				"operationId": "createPets",
				"tags": [
					"pets"
				],
				"responses": {
					"201": {
						"description": "Null response"
					},
					"default": {
						"description": "unexpected error",
						"content": {
							"application/json": {
								"schema": {
									"$ref": "#/components/schemas/Error"
								}
							}
						}
					}
				}
			}
		},
		"/pets/{petId}": {
			"get": {
				"summary": "Info for a specific pet",
				"operationId": "showPetById",
				"tags": [
					"pets"
				],
				"parameters": [
					{
						"name": "petId",
						"in": "path",
						"required": true,
						"description": "The id of the pet to retrieve",
						"schema": {
							"type": "string"
						}
					}
				],
				"responses": {
					"200": {
						"description": "Expected response to a valid request",
						"content": {
							"application/json": {
								"schema": {
									"$ref": "#/components/schemas/Pets"
								}
							}
						}
					},
					"default": {
						"description": "unexpected error",
						"content": {
							"application/json": {
								"schema": {
									"$ref": "#/components/schemas/Error"
								}
							}
						}
					}
				}
			}
		}
	},
	"components": {
		"schemas": {
			"Pet": {
				"required": [
					"id",
					"name"
				],
				"properties": {
					"id": {
						"type": "integer",
						"format": "int64"
					},
					"name": {
						"type": "string"
					},
					"tag": {
						"type": "string"
					}
				}
			},
			"Pets": {
				"type": "array",
				"items": {
					"$ref": "#/components/schemas/Pet"
				}
			},
			"Error": {
				"required": [
					"code",
					"message"
				],
				"properties": {
					"code": {
						"type": "integer",
						"format": "int32"
					},
					"message": {
						"type": "string"
					}
				}
			}
		}
	}
};

// create a new instance of spectral with all of the baked in rulesets
const spectral = new Spectral();

spectral.addFunctions(oas3Functions());
spectral.addRules(oas3Rules());

spectral.addRules({
  // .. extend with your own custom rules
});

// run!
const results = spectral.run(myOAS);

console.log(JSON.stringify(results, null, 4));