diff --git a/src/adapters/hiromedia.js b/src/adapters/hiromedia.js
index 856ee629060..8bef4bc6cd3 100644
--- a/src/adapters/hiromedia.js
+++ b/src/adapters/hiromedia.js
@@ -1,24 +1,21 @@
-/* jslint white:true, browser:true, single: true */
-/* global $$PREBID_GLOBAL$$, require, module */
-
-/**
+/**
  * Adapter for HIRO Media
  *
  * @module HiroMediaAdapter
  *
- * @requires src/adloader
+ * @requires src/ajax
  * @requires src/bidfactory
  * @requires src/bidmanager
  * @requires src/constants
  * @requires src/utils
  */
-var adloader = require('src/adloader');
+var Ajax = require('src/ajax');
 var bidfactory = require('src/bidfactory');
 var bidmanager = require('src/bidmanager');
 var utils = require('src/utils');
 var STATUS = require('src/constants').STATUS;
 
-var HiroMediaAdapter = function HiroMediaAdapter() {
+var HiroMediaAdapter = function HiroMediaAdapter() {
   'use strict';
 
   /**
@@ -43,7 +40,7 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    * Default bid param values
    *
    * @memberof module:HiroMediaAdapter~
-   * @constant {module:HiroMediaAdapter~bidParams}
+   * @constant {array.<string>}
    * @private
    */
   var REQUIRED_BID_PARAMS = ['accountId'];
@@ -60,16 +57,17 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
   };
 
   /**
-   * Storage for bid objects.
-   *
-   * Bids need to be stored between requests and response since the response
-   * is a global callback.
+   * Returns true if the given value is `undefined`
    *
    * @memberof module:HiroMediaAdapter~
-   * @var {array.<module:HiroMediaAdapter~bidInfo>}
    * @private
+   *
+   * @param  {*} value value to check
+   * @return {boolean} true if the given value is `undefined`, false otherwise
    */
-  var _bidStorage = [];
+  function isUndefined(value) {
+    return typeof value === 'undefined';
+  }
 
   /**
    * Call bidmanager.addBidResponse
@@ -80,14 +78,14 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    * @memberof module:HiroMediaAdapter~
    * @private
    *
-   * @param  {module:HiroMediaAdapter~bidInfo} bidInfo bid object wrapper to respond for
+   * @param  {object} bid bid object connected to the response
    * @param  {object|boolean} [bidResponse] response object for bid, if not
    * set the response will be an empty bid response.
    */
-  function addBidResponse(bidInfo, bidResponse) {
-    var placementCode = bidInfo.bid.placementCode;
+  function addBidResponse(bid, bidResponse) {
+    var placementCode = bid.placementCode;
     var bidStatus = bidResponse ? STATUS.GOOD : STATUS.NO_BID;
-    var bidObject = bidfactory.createBid(bidStatus, bidInfo.bid);
+    var bidObject = bidfactory.createBid(bidStatus, bid);
 
     bidObject.bidderCode = BIDDER_CODE;
 
@@ -99,7 +97,7 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
     }
 
     utils.logMessage('hiromedia.callBids, addBidResponse for ' + placementCode + ' status: ' + bidStatus);
-    bidmanager.addBidResponse(placementCode, bidObject);
+    bidmanager.addBidResponse(placementCode, bidObject);
   }
 
   /**
@@ -121,35 +119,19 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    * @memberof module:HiroMediaAdapter~
    * @private
    *
-   * @param  {object} response [description]
+   * @param  {object} response bid response object
+   * @param  {object} bid bid object connected to response
    */
-  function handleResponse(response) {
-    _bidStorage.filter(function (bidInfo) {
-      return bidInfo.batchKey === response.batchKey;
-    }).forEach(function (bidInfo) {
-      // Sample the bid responses according to `response.chance`,
-      // if `response.chance` is not provided, sample at 100%.
-      if (response.chance === undefined || checkChance(response.chance)) {
-        addBidResponse(bidInfo, response);
-      } else {
-        addBidResponse(bidInfo, false);
-      }
-    });
+  function handleResponse(response, bid) {
+    // Sample the bid responses according to `response.chance`,
+    // if `response.chance` is not provided, sample at 100%.
+    if (isUndefined(response.chance) || checkChance(response.chance)) {
+      addBidResponse(bid, response);
+    } else {
+      addBidResponse(bid, false);
+    }
   }
 
-  /**
-   * Call {@linkcode module:HiroMediaAdapter~handleResponse} for valid responses
-   *
-   * @global
-   *
-   * @param  {object} [response] the response from the server
-   */
-  $$PREBID_GLOBAL$$.hiromedia_callback = function (response) {
-    if (response && response.batchKey) {
-      handleResponse(response);
-    }
-  };
-
   /**
    * Find browser name and version
    *
@@ -161,7 +143,7 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    * @return {module:HiroMediaAdapter~browserInfo} object containing name and version of browser
    * or empty strings.
    */
-  function getBrowser() {
+  function getBrowser() {
     var ua = navigator.userAgent;
     var browsers = [{
       name: 'Mobile',
@@ -184,7 +166,7 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
     var name = '';
     var version = '';
 
-    browsers.some(function (browser) {
+    browsers.some(function (browser) {
       var nameSearch = browser.stringSearch || browser.name;
       var defaultVersionSearch = nameSearch + '\\/(\\d+)';
       var versionSearch = browser.versionSearch || defaultVersionSearch;
@@ -197,13 +179,13 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
           version = versionMatch && versionMatch[1];
         }
         return true;
-      }
+      }
     });
 
     return {
       name: name,
       version: version
-    };
+    };
   }
 
   /**
@@ -214,10 +196,10 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    *
    * @return {string}  domain of top context url.
    */
-  function getDomain() {
+  function getDomain() {
     var a = document.createElement('a');
     a.href = utils.getTopWindowUrl();
-    return a.hostname;
+    return a.hostname;
   }
 
   /**
@@ -235,97 +217,49 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
   }
 
   /**
-   * Calculate and return a batchKey key for a bid
-   *
-   * Bid of similar placement can have similar responses,
-   * we can calculate a key based on the variant properties
-   * of a bid which can share the same response
+   * Build a {@linkcode module:HiroMediaAdapter~bidInfo|bidInfo} object based on a
+   * bid sent to {@linkcode module:HiroMediaAdapter#callBids|callBids}
    *
    * @memberof module:HiroMediaAdapter~
    * @private
    *
-   * @param  {module:HiroMediaAdapter~bidInfo} bidInfo bid information
-   * @return {string}  batch key for bid
+   * @param  {object} bid bid from `Prebid.js`
+   * @return {module:HiroMediaAdapter~bidInfo} information for bid request
    */
-  function getBatchKey(bidInfo) {
-    var bidParams = bidInfo.bidParams;
-    var batchParams = [
-      bidParams.bidUrl,
-      bidParams.accountId,
-      bidInfo.selectedSize,
-      bidInfo.additionalSizes
-    ];
-
-    return batchParams.join('-');
+  function processBid(bid) {
+    var sizes = utils.parseSizesInput(bid.sizes);
+    var bidParams = defaultParams(bid.params);
+    var hasValidBidRequest = utils.hasValidBidRequest(bidParams, REQUIRED_BID_PARAMS, BIDDER_CODE);
+    var shouldBid = hasValidBidRequest;
+    var bidInfo = {
+      bidParams: bidParams,
+      shouldBid: shouldBid,
+      selectedSize: sizes[0],
+      additionalSizes: sizes.slice(1).join(',')
+    };
+
+    return bidInfo;
   }
 
   /**
-   * Build a set of {@linkcode module:HiroMediaAdapter~bidInfo|bidInfo} objects based on the
-   * bids sent to {@linkcode module:HiroMediaAdapter#callBids|callBids}
+   * Wrapper around `JSON.parse()` that returns false on error
    *
    * @memberof module:HiroMediaAdapter~
    * @private
    *
-   * @param  {object} bids bids sent from `Prebid.js`
-   * @return {array.<module:HiroMediaAdapter~bidInfo>} wrapped bids
+   * @param  {string} text potential JSON string to convert to object
+   * @return {object|boolean} object parsed from text or `false` in case of and error
    */
-  function processBids(bids) {
-    var result = [];
-
-    if (bids) {
-      utils.logMessage('hiromedia.processBids, processing ' + bids.length + ' bids');
-
-      bids.forEach(function (bid) {
-        var sizes = utils.parseSizesInput(bid.sizes);
-        var bidParams = defaultParams(bid.params);
-        var hasValidBidRequest = utils.hasValidBidRequest(bidParams, REQUIRED_BID_PARAMS, BIDDER_CODE);
-        var shouldBid = hasValidBidRequest;
-        var bidInfo = {
-          bid: bid,
-          bidParams: bidParams,
-          shouldBid: shouldBid,
-          selectedSize: sizes[0],
-          additionalSizes: sizes.slice(1).join(',')
-        };
-
-        if (shouldBid) {
-          bidInfo.batchKey = getBatchKey(bidInfo);
-        }
+  function tryJson(text) {
+    var object = false;
 
-        result.push(bidInfo);
-      });
+    try {
+      object = JSON.parse(text);
+    } catch (ignore) {
+      // Ignored
     }
 
-    return result;
-  }
-
-  /**
-   * Send a bid request to the bid server endpoint
-   *
-   * Calls `adLoader.loadScript`
-   *
-   * @memberof module:HiroMediaAdapter~
-   * @private
-   *
-   * @param  {string} url base url, can already contain query parameters
-   * @param  {object} requestParams parameters to add to query
-   */
-  function sendBidRequest(url, requestParams) {
-    if (requestParams) {
-      if (url.indexOf('?') !== -1) {
-        url = url + '&';
-      } else {
-        url = url + '?';
-      }
-
-      Object.keys(requestParams).forEach(function (key) {
-        url = utils.tryAppendQueryString(url, key, requestParams[key]);
-      });
-    }
-
-    utils.logMessage('hiromedia.callBids, url:' + url);
-
-    adloader.loadScript(url);
+    return object;
   }
 
   /**
@@ -335,56 +269,65 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    *
    * @param  {object} params placement and bid data from `Prebid.js`
    */
-  function _callBids(params) {
+  function _callBids(params) {
     var browser = getBrowser();
     var domain = getDomain();
-    var bidsRequested = {};
+    var bids = params && params.bids;
+    var ajaxOptions = {
+      method: 'GET',
+      withCredentials: true
+    };
+
+    // Fixed data, shared by all requests
+    var fixedRequest = {
+      adapterVersion: ADAPTER_VERSION,
+      browser: browser.name,
+      browserVersion: browser.version,
+      domain: domain
+    };
 
     utils.logMessage('hiromedia.callBids');
 
-    if (params) {
-      // Processed bids are stored in the adapter scope
-      _bidStorage = processBids(params.bids);
-    } else {
-      // Ensure we don't run on stale data
-      _bidStorage = [];
-    }
-
-    if (_bidStorage.length) {
-      // Loop over processed bids and send a request if a request for the bid
-      // batchKey has not been sent.
-      _bidStorage.forEach(function (bidInfo) {
-        var bid = bidInfo.bid;
-        var batchKey = bidInfo.batchKey;
+    if (bids && bids.length) {
+      bids.forEach(function (bid) {
+        var bidInfo = processBid(bid);
         var bidParams = bidInfo.bidParams;
-
         utils.logMessage('hiromedia.callBids, bidInfo ' + bid.placementCode + ' ' + bidInfo.shouldBid);
-
         if (bidInfo.shouldBid) {
           var url = bidParams.bidUrl;
-
-          if (!bidsRequested[batchKey]) {
-            bidsRequested[batchKey] = true;
-
-            sendBidRequest(url, {
-              adapterVersion: ADAPTER_VERSION,
-              callback: '$$PREBID_GLOBAL$$.hiromedia_callback',
-              batchKey: batchKey,
-              placementCode: bid.placementCode,
-              accountId: bidParams.accountId,
-              browser: browser.name,
-              browserVersion: browser.version,
-              domain: domain,
-              selectedSize: bidInfo.selectedSize,
-              additionalSizes: bidInfo.additionalSizes
-            });
-          }
-        } else {
+          var requestParams = Object.assign({}, fixedRequest, bidInfo.bidParams, {
+            placementCode: bid.placementCode,
+            selectedSize: bidInfo.selectedSize,
+            additionalSizes: bidInfo.additionalSizes
+          });
+
+          Object.keys(requestParams).forEach(function (key) {
+            if (requestParams[key] === '' || isUndefined(requestParams[key])) {
+              delete requestParams[key];
+            }
+          });
+
+          utils.logMessage('hiromedia.callBids, bid request ' + url + ' ' + JSON.stringify(bidInfo.bidRequest));
+
+          Ajax.ajax(url, {
+
+            success: function(responseText) {
+              var response = tryJson(responseText);
+              handleResponse(response, bid);
+            },
+
+            error: function(err, xhr) {
+              utils.logError('hiromedia.callBids, bid request error', xhr.status, err);
+              addBidResponse(bid, false);
+            }
+
+          }, requestParams, ajaxOptions);
+        } else {
           // No bid
-          addBidResponse(bidInfo, false);
-        }
-      });
-    }
+          addBidResponse(bid, false);
+        }
+      });
+    }
   }
 
   return {
@@ -409,10 +352,8 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    * @typedef {object} module:HiroMediaAdapter~bidInfo
    * @private
    *
-   * @property {object} bid original bid passed to #callBids
    * @property {string} selectedSize the first size in the the placement sizes array
    * @property {string} additionalSizes list of sizes in the placement sizes array besides the first
-   * @property {string} batchKey key used for batching requests which have the same basic properties
    * @property {module:HiroMediaAdapter~bidParams} bidParams original params passed for bid in #callBids
    * @property {boolean} shouldBid flag to determine if the bid is valid for bidding or not
    */
@@ -425,7 +366,7 @@ var HiroMediaAdapter = function HiroMediaAdapter() {
    *
    * @property {string} name browser name (e.g. `'Chrome'` or `'Firefox'`)
    * @property {string} version browser major version (e.g. `'53'`)
-   */
+   */
 };
 
 module.exports = HiroMediaAdapter;
diff --git a/test/spec/adapters/hiromedia_spec.js b/test/spec/adapters/hiromedia_spec.js
index 4fe7a0ec1cd..643379b4ff2 100644
--- a/test/spec/adapters/hiromedia_spec.js
+++ b/test/spec/adapters/hiromedia_spec.js
@@ -1,36 +1,30 @@
-/* jslint white: true, es6: true, single: true */
-/* jshint esversion:6 */
-
-import { expect } from 'chai';
-import querystringify from 'querystringify';
+import { expect } from 'chai';
 import urlParse from 'url-parse';
 
-import adloader from 'src/adloader';
 import Adapter from 'src/adapters/hiromedia';
 import bidmanager from 'src/bidmanager';
 import { STATUS } from 'src/constants';
 import * as utils from 'src/utils';
 
-describe('hiromedia adapter', function () {
+describe('hiromedia adapter', function () {
   const BIDDER_CODE = 'hiromedia';
-  const DEFAULT_CALLBACK_NAME = 'hiromedia_callback';
   const DEFAULT_ENDPOINT = 'https://hb-rtb.ktdpublishers.com/bid/get';
 
   let adapter;
   let sandbox;
-  let loadScriptStub;
+  let xhr;
   let addBidResponseStub;
   let hasValidBidRequestSpy;
   let placementId = 0;
 
   window.$$PREBID_GLOBAL$$ = window.$$PREBID_GLOBAL$$ || {};
 
-  beforeEach(() => {
+  beforeEach(() => {
     adapter = new Adapter();
     sandbox = sinon.sandbox.create();
 
     // Used to spy on bid requests
-    loadScriptStub = sandbox.stub(adloader, 'loadScript');
+    xhr = sandbox.useFakeXMLHttpRequest();
 
     // Used to spy on bid responses
     addBidResponseStub = sandbox.stub(bidmanager, 'addBidResponse');
@@ -38,7 +32,7 @@ describe('hiromedia adapter', function () {
     // Used to spy on bid validation
     hasValidBidRequestSpy = sandbox.spy(utils, 'hasValidBidRequest');
 
-    placementId = 0;
+    placementId = 0;
   });
 
   afterEach(() => {
@@ -47,13 +41,13 @@ describe('hiromedia adapter', function () {
 
   // Helper function that asserts that no bidding activity (requests nor responses)
   // was made during a test.
-  const assertNoBids = () => {
-    sinon.assert.notCalled(loadScriptStub);
-    sinon.assert.notCalled(addBidResponseStub);
+  const assertNoBids = () => {
+    expect(xhr.requests.length).to.be.equal(0);
+    sinon.assert.notCalled(addBidResponseStub);
   };
 
   // Helper function to generate a 'mock' bid object
-  const makePlacement = (size) => {
+  const makePlacement = (size) => {
     placementId += 1;
 
     return {
@@ -63,7 +57,7 @@ describe('hiromedia adapter', function () {
         accountId: '1337'
       },
       placementCode: 'div-gpt-ad-12345-' + placementId
-    };
+    };
   };
 
   // 300x250 are in the allowed size by default
@@ -72,7 +66,7 @@ describe('hiromedia adapter', function () {
   // anything else should have no bid by default
   const leaderPlacement = () => makePlacement([728, 90]);
 
-  describe('callbids', () => {
+  describe('callbids', () => {
     it('exists and is a function', () => {
       expect(adapter.callBids).to.exist.and.to.be.a('function');
     });
@@ -92,51 +86,50 @@ describe('hiromedia adapter', function () {
       assertNoBids();
     });
 
-    it('invokes a bid request per placement', () => {
+    it('invokes a bid request per placement', () => {
       const expectedRequests = [{
-        batchKey: [DEFAULT_ENDPOINT, '1337', '300x250', ''].join('-'),
         placementCode: 'div-gpt-ad-12345-1',
         selectedSize: '300x250'
       }, {
-        batchKey: [DEFAULT_ENDPOINT, '1337', '728x90', ''].join('-'),
         placementCode: 'div-gpt-ad-12345-2',
         selectedSize: '728x90'
+      }, {
+        placementCode: 'div-gpt-ad-12345-3',
+        selectedSize: '300x250'
       }];
 
       const params = {
-        bids: [tilePlacement(), leaderPlacement()]
+        bids: [tilePlacement(), leaderPlacement(), tilePlacement()]
       };
 
       adapter.callBids(params);
-      sinon.assert.calledTwice(loadScriptStub);
+      expect(xhr.requests.length).to.equal(3);
       sinon.assert.notCalled(addBidResponseStub);
-      sinon.assert.calledTwice(hasValidBidRequestSpy);
+      sinon.assert.calledThrice(hasValidBidRequestSpy);
 
-      expectedRequests.forEach(function(request, index) {
+      expectedRequests.forEach(function(request, index) {
         expect(hasValidBidRequestSpy.returnValues[index]).to.be.equal(true);
 
         // validate request
-        const bidRequest = loadScriptStub.getCall(index).args[0];
+        const bidRequest = xhr.requests[index].url;
         const defaultBidUrl = urlParse(DEFAULT_ENDPOINT);
-        const bidUrl = urlParse(bidRequest);
-        const query = querystringify.parse(bidUrl.query);
+        const bidUrl = urlParse(bidRequest, true);
+        const query = bidUrl.query;
 
         expect(bidUrl.hostname).to.equal(defaultBidUrl.hostname);
         expect(bidUrl.pathname).to.equal(defaultBidUrl.pathname);
 
         expect(query).to.have.property('adapterVersion').and.to.equal('3');
-        expect(query).to.have.property('callback').and.to.equal('$$PREBID_GLOBAL$$.' + DEFAULT_CALLBACK_NAME);
-        expect(query).to.have.property('batchKey').and.to.equal(request.batchKey);
         expect(query).to.have.property('placementCode').and.to.equal(request.placementCode);
         expect(query).to.have.property('accountId').and.to.equal('1337');
         expect(query).to.have.property('selectedSize').and.to.equal(request.selectedSize);
         expect(query).to.not.have.property('additionalSizes');
-        expect(query).to.have.property('domain').and.to.equal(window.top.location.hostname);
-      });
+        expect(query).to.have.property('domain').and.to.equal(window.top.location.hostname);
+      });
     });
 
     // Test additionalSizes parameter
-    it('attaches multiple sizes to additionalSizes', () => {
+    it('attaches multiple sizes to additionalSizes', () => {
       const placement = tilePlacement();
 
       // Append additional
@@ -148,18 +141,18 @@ describe('hiromedia adapter', function () {
       };
 
       adapter.callBids(params);
-      sinon.assert.calledOnce(loadScriptStub);
+      expect(xhr.requests.length).to.be.equal(1);
 
-      const bidRequest = loadScriptStub.getCall(0).args[0];
-      const bidUrl = urlParse(bidRequest);
-      const query = querystringify.parse(bidUrl.query);
+      const bidRequest = xhr.requests[0].url;
+      const bidUrl = urlParse(bidRequest, true);
+      const query = bidUrl.query;
 
       expect(query).to.have.property('selectedSize').and.to.equal('300x250');
-      expect(query).to.have.property('additionalSizes').and.to.equal('300x600,300x900');
+      expect(query).to.have.property('additionalSizes').and.to.equal('300x600,300x900');
     });
 
     // Test `params.accountId` validation
-    it('invalidates bids with no id', () => {
+    it('invalidates bids with no id', () => {
       const placement = tilePlacement();
       delete placement.params;
 
@@ -168,13 +161,20 @@ describe('hiromedia adapter', function () {
       };
 
       adapter.callBids(params);
-      sinon.assert.notCalled(loadScriptStub);
+      expect(xhr.requests.length).to.be.equal(0);
       sinon.assert.calledOnce(hasValidBidRequestSpy);
-      expect(hasValidBidRequestSpy.returnValues[0]).to.be.equal(false);
+      sinon.assert.calledOnce(addBidResponseStub);
+
+      expect(hasValidBidRequestSpy.returnValues[0]).to.be.equal(false);
+      const placementCode = addBidResponseStub.getCall(0).args[0];
+      const bidObject = addBidResponseStub.getCall(0).args[1];
+
+      expect(placementCode).to.be.equal('div-gpt-ad-12345-1');
+      expect(bidObject.getStatusCode()).to.be.equal(STATUS.NO_BID);
     });
 
     // Test `params.bidUrl`
-    it('accepts a custom bid endpoint url', () => {
+    it('accepts a custom bid endpoint url', () => {
       const placement = tilePlacement();
       placement.params.bidUrl = DEFAULT_ENDPOINT + '?someparam=value';
 
@@ -183,73 +183,76 @@ describe('hiromedia adapter', function () {
       };
 
       adapter.callBids(params);
-      sinon.assert.calledOnce(loadScriptStub);
+      expect(xhr.requests.length).to.be.equal(1);
 
-      const bidRequest = loadScriptStub.getCall(0).args[0];
+      const bidRequest = xhr.requests[0].url;
       const defaultBidUrl = urlParse(DEFAULT_ENDPOINT);
-      const bidUrl = urlParse(bidRequest);
-      const query = querystringify.parse(bidUrl.query);
+      const bidUrl = urlParse(bidRequest, true);
+      const query = bidUrl.query;
 
       expect(bidUrl.hostname).to.equal(defaultBidUrl.hostname);
       expect(bidUrl.pathname).to.equal(defaultBidUrl.pathname);
 
-      expect(query).to.have.property('someparam').and.to.equal('value');
-    });
-
-    it('batches similar bid requests for similar sized placements', () => {
-      const params = {
-        bids: [tilePlacement(), tilePlacement()]
-      };
-
-      adapter.callBids(params);
-      sinon.assert.calledOnce(loadScriptStub); // and only once!
+      expect(query).to.have.property('someparam').and.to.equal('value');
     });
-  });
+  });
+
+  describe('response handler', () => {
+    let server;
+
+    beforeEach(() => {
+      server = sandbox.useFakeServer();
+    });
+
+    const assertSingleFailedBidResponse = () => {
+      sinon.assert.calledOnce(addBidResponseStub);
+      const placementCode = addBidResponseStub.getCall(0).args[0];
+      const bidObject = addBidResponseStub.getCall(0).args[1];
+
+      expect(placementCode).to.be.equal('div-gpt-ad-12345-1');
+      expect(bidObject.getStatusCode()).to.be.equal(STATUS.NO_BID);
+    };
+
+    it('tolerates an empty response', () => {
+      server.respondWith('');
+      adapter.callBids({bids: [tilePlacement()]});
+      server.respond();
+
+      assertSingleFailedBidResponse();
+    });
 
-  describe('global response handler', () => {
-    const getPbjs = () => window.$$PREBID_GLOBAL$$;
-    const getResponseHandler = () => window.$$PREBID_GLOBAL$$[DEFAULT_CALLBACK_NAME];
+    it('tolerates a response error', () => {
+      server.respondWith([500, {}, '']);
+      adapter.callBids({bids: [tilePlacement()]});
+      server.respond();
 
-    it('exists and is a function', () => {
-      expect(getResponseHandler()).to.exist.and.to.be.a('function');
+      assertSingleFailedBidResponse();
     });
 
-    it('tolerates empty arguments', () => {
-      expect(getResponseHandler()).to.not.throw(Error);
-    });
+    it('tolerates an invalid response', () => {
+      server.respondWith('not json');
+      adapter.callBids({bids: [tilePlacement()]});
+      server.respond();
 
-    it('tolerates an empty response', () => {
-      expect(getResponseHandler().bind(getPbjs(), {})).to.not.throw(Error);
+      assertSingleFailedBidResponse();
     });
 
-    // This test is coupled with `callBids`, this is done
-    // to ensure that the response handler is able to
-    // add bid responses for each placement with the same
-    // batch key.
-    // To do this, we have to have the internal state of
-    // the adapter set up correctly.
-    it('adds a bid reponse for each pending bid', () => {
-      const expectedResponses = [{
-        batchKey: [DEFAULT_ENDPOINT, '1337', '300x250', ''].join('-'),
+    it('adds a bid reponse for each pending bid', () => {
+      const responses = [{
         width: '300',
         height: '250',
         cpm: 0.4,
         ad: '<script src="ad.js"></script>'
       }, {
-        batchKey: [DEFAULT_ENDPOINT, '1337', '728x90', ''].join('-'),
         width: '728',
         height: '90',
         cpm: 0.4,
         ad: '<script src="ad.js"></script>'
       }];
 
-      // Instead of the dead stub defined in the top scope, we'll use
-      // one that mocks a response.
-      loadScriptStub.restore();
       let id = 0;
-      const activeLoadScriptStub = sandbox.stub(adloader, 'loadScript', (url) => {
-        const handler = getResponseHandler();
-        handler(expectedResponses[id]);
+      server.respondWith((request) => {
+        request.respond(200, {}, JSON.stringify(responses[id]));
         id += 1;
       });
 
@@ -258,11 +261,12 @@ describe('hiromedia adapter', function () {
       };
 
       adapter.callBids(params);
+      server.respond();
 
-      sinon.assert.calledTwice(activeLoadScriptStub);
+      expect(server.requests.length).to.be.equal(2);
       sinon.assert.calledTwice(addBidResponseStub);
 
-      expectedResponses.forEach((expectedResponse, i) => {
+      responses.forEach((expectedResponse, i) => {
         const placementCode = addBidResponseStub.getCall(i).args[0];
         const bidObject = addBidResponseStub.getCall(i).args[1];
 
@@ -272,17 +276,16 @@ describe('hiromedia adapter', function () {
         expect(bidObject).to.have.property('cpm').and.to.equal(expectedResponse.cpm);
         expect(bidObject).to.have.property('ad').and.to.equal(expectedResponse.ad);
         expect(bidObject).to.have.property('width').and.to.equal(expectedResponse.width);
-        expect(bidObject).to.have.property('height').and.to.equal(expectedResponse.height);
-      });
+        expect(bidObject).to.have.property('height').and.to.equal(expectedResponse.height);
+      });
     });
 
     // We want to check that responses are added according to a sampling value,
     // this is possible by stubbing `Math.random`, to ensure the effect is
     // limited to the area we check, we create a self destructing stub which
     // restores itself once called.
-    it('adds responses according to the sampling defined in the response', () => {
+    it('adds responses according to the sampling defined in the response', () => {
       const response = {
-        batchKey: [DEFAULT_ENDPOINT, '1337', '300x250', ''].join('-'),
         cpm: 0.4,
         chance: 0.25,
         ad: '<script src="ad.js"></script>'
@@ -293,22 +296,19 @@ describe('hiromedia adapter', function () {
       const randomValues = [0.2, 0.3];
       let randomIndex = 0;
 
-      loadScriptStub.restore();
-      const activeLoadScriptStub = sandbox.stub(adloader, 'loadScript', (url) => {
-        const handler = getResponseHandler();
-
-        const mathRandomStub = sandbox.stub(Math, 'random', function () {
+      server.respondWith((request) => {
+        const mathRandomStub = sandbox.stub(Math, 'random', function () {
           const randomValue = randomValues[randomIndex];
 
           randomIndex += 1;
           mathRandomStub.restore(); // self destruct on call
 
-          return randomValue;
+          return randomValue;
         });
 
-        handler(response);
+        request.respond(200, {}, JSON.stringify(response));
 
-        mathRandomStub.restore();
+        mathRandomStub.restore();
       });
 
       const params = {
@@ -317,6 +317,7 @@ describe('hiromedia adapter', function () {
 
       adapter.callBids(params);
       adapter.callBids(params);
+      server.respond();
 
       sinon.assert.calledTwice(addBidResponseStub);
 
@@ -324,7 +325,7 @@ describe('hiromedia adapter', function () {
       const secondBidObject = addBidResponseStub.getCall(1).args[1];
 
       expect(firstBidObject.getStatusCode()).to.be.equal(STATUS.GOOD);
-      expect(secondBidObject.getStatusCode()).to.be.equal(STATUS.NO_BID);
-    });
-  });
+      expect(secondBidObject.getStatusCode()).to.be.equal(STATUS.NO_BID);
+    });
+  });
 });