c.ApiKey("auth")
 .Description("API Key Authentication")
 .Name("auth")
 .In("query");

c.InjectJavaScript(thisAssembly, "SwashbuckleCustomAuth.CustomContent.basic-auth.js");

$('#explore').off();

$('#explore').click(function () {
   var key = $('#input_apiKey')[0].value;
   var credentials = key.split(':'); //username:password expected

$.ajax({
    url: "yourAuthEndpoint",
    type: "post",
    contenttype: 'x-www-form-urlencoded',
    data: "grant_type=password&username=" + credentials[0] + "&password=" + credentials[1],
    success: function (response) {
        var bearerToken = 'Bearer ' + response.access_token;

        window.swaggerUi.api.clientAuthorizations.add('Authorization', new SwaggerClient.ApiKeyAuthorization('Authorization', bearerToken, 'header'));
        window.swaggerUi.api.clientAuthorizations.remove("api_key");
        alert("Login successfull");
       },
       error: function (xhr, ajaxoptions, thrownerror) {
        alert("Login failed!");
       }
    });
});

function addApiKeyAuthorization() {
        var key = encodeURIComponent($('#input_apiKey')[0].value);
        if (key && key.trim() != "") {
            var apiKeyAuth = new SwaggerClient.ApiKeyAuthorization("NAME OF PARAMETER", key, "query");
            window.swaggerUi.api.clientAuthorizations.add("api_key", apiKeyAuth);
            log("added key " + key);
        }
    }

{
  "swagger": "2.0",
  "info": {
    "description": "API Documentation",
    "version": "1.0.2",
    "title": "my super service"
  },
  "basePath": "/my-super-services/api",
  "host": "example.com",
  "schemes": [
    "https",
    "http"
  ],
  "securityDefinitions": {
    "UserSecurity": {
      "type": "apiKey",
      "in": "header",       <----- set this to header or cookie or query
      "name": "X-Api-Key"   <----- you custom key goes here
    }
  },