diff --git a/modules/serverbidServerBidAdapter.js b/modules/serverbidServerBidAdapter.js
new file mode 100644
index 00000000000..47d4e518222
--- /dev/null
+++ b/modules/serverbidServerBidAdapter.js
@@ -0,0 +1,236 @@
+import Adapter from 'src/adapter';
+import bidfactory from 'src/bidfactory';
+import * as utils from 'src/utils';
+import adaptermanager from 'src/adaptermanager';
+import { STATUS, S2S } from 'src/constants';
+import { config } from 'src/config';
+
+const TYPE = S2S.SRC;
+const getConfig = config.getConfig;
+const REQUIRED_S2S_CONFIG_KEYS = ['siteId', 'networkId', 'bidders', 'endpoint'];
+
+let _s2sConfig;
+config.setDefaults({
+  's2sConfig': {
+    enabled: false,
+    timeout: 1000,
+    adapter: 'serverbidServer'
+  }
+});
+
+var ServerBidServerAdapter;
+ServerBidServerAdapter = function ServerBidServerAdapter() {
+  const baseAdapter = new Adapter('serverbidServer');
+
+  const BASE_URI = 'https://e.serverbid.com/api/v2';
+
+  const sizeMap = [
+    null,
+    '120x90',
+    '120x90',
+    '468x60',
+    '728x90',
+    '300x250',
+    '160x600',
+    '120x600',
+    '300x100',
+    '180x150',
+    '336x280',
+    '240x400',
+    '234x60',
+    '88x31',
+    '120x60',
+    '120x240',
+    '125x125',
+    '220x250',
+    '250x250',
+    '250x90',
+    '0x0',
+    '200x90',
+    '300x50',
+    '320x50',
+    '320x480',
+    '185x185',
+    '620x45',
+    '300x125',
+    '800x250'
+  ];
+
+  sizeMap[77] = '970x90';
+  sizeMap[123] = '970x250';
+  sizeMap[43] = '300x600';
+
+  function setS2sConfig(options) {
+    let contains = (xs, x) => xs.indexOf(x) > -1;
+    let userConfig = Object.keys(options);
+
+    REQUIRED_S2S_CONFIG_KEYS.forEach(key => {
+      if (!contains(userConfig, key)) {
+        utils.logError(key + ' missing in server to server config');
+        return void 0; // void 0 to beat the linter
+      }
+    })
+
+    _s2sConfig = options;
+  }
+  getConfig('s2sConfig', ({s2sConfig}) => setS2sConfig(s2sConfig));
+
+  function getLocalConfig() {
+    return (_s2sConfig || {});
+  }
+
+  function _convertFields(bid) {
+    let safeBid = bid || {};
+    let converted = {};
+    let name = safeBid.bidder;
+    converted[name] = safeBid.params;
+    return converted;
+  }
+
+  baseAdapter.callBids = function(s2sBidRequest, bidRequests, addBidResponse, done, ajax) {
+    let params = s2sBidRequest;
+    let shouldDoWorkFn = function(bidRequest) {
+      return bidRequest &&
+        bidRequest.ad_units &&
+        utils.isArray(bidRequest.ad_units) &&
+        bidRequest.ad_units.length;
+    }
+    if (shouldDoWorkFn(params)) {
+      _callBids(s2sBidRequest, bidRequests, addBidResponse, done, ajax);
+    }
+  };
+
+  function _callBids(s2sBidRequest, bidRequests, addBidResponse, done, ajax) {
+    let bidRequest = s2sBidRequest;
+
+    // one request per ad unit
+    for (let i = 0; i < bidRequest.ad_units.length; i++) {
+      let adunit = bidRequest.ad_units[i];
+      let siteId = _s2sConfig.siteId;
+      let networkId = getLocalConfig().networkId;
+      let sizes = adunit.sizes;
+
+      const data = {
+        placements: [],
+        time: Date.now(),
+        user: {},
+        url: utils.getTopWindowUrl(),
+        referrer: document.referrer,
+        enableBotFiltering: true,
+        includePricingData: true,
+        parallel: true
+      };
+
+      const bids = adunit.bids || [];
+
+      // one placement for each of the bids
+      for (let i = 0; i < bids.length; i++) {
+        const bid = bids[i];
+        bid.code = adunit.code;
+
+        const placement = Object.assign({}, {
+          divName: bid.bid_id,
+          networkId: networkId,
+          siteId: siteId,
+          adTypes: bid.adTypes || getSize(sizes),
+          bidders: _convertFields(bid),
+          skipSelection: true
+        });
+
+        if (placement.networkId && placement.siteId) {
+          data.placements.push(placement);
+        }
+      }
+      if (data.placements.length) {
+        ajax(BASE_URI, _responseCallback(addBidResponse, bids), JSON.stringify(data), { method: 'POST', withCredentials: true, contentType: 'application/json' });
+      }
+    }
+  }
+
+  function _responseCallback(addBidResponse, bids) {
+    return function (resp) {
+      let bid;
+      let bidId;
+      let result;
+      let bidObj;
+      let bidCode;
+      let placementCode;
+      let skipSelectionRequestsReturnArray = function (decision) {
+        return (decision || []).length ? decision[0] : {};
+      };
+
+      try {
+        result = JSON.parse(resp);
+      } catch (error) {
+        utils.logError(error);
+      }
+
+      for (let i = 0; i < bids.length; i++) {
+        bidObj = bids[i];
+        bidId = bidObj.bid_id;
+        bidObj.bidId = bidObj.bid_id;
+        bidCode = bidObj.bidder;
+        placementCode = bidObj.code;
+        let noBid = function(bidObj) {
+          bid = bidfactory.createBid(STATUS.NO_BID, bidObj);
+          bid.bidderCode = bidCode;
+          return bid;
+        };
+
+        if (result) {
+          const decision = result.decisions && skipSelectionRequestsReturnArray(result.decisions[bidId]);
+          const price = decision && decision.pricing && decision.pricing.clearPrice;
+
+          if (decision && price) {
+            bid = bidfactory.createBid(STATUS.GOOD, bidObj);
+            bid = Object.assign(bid, {bidderCode: bidCode,
+              cpm: price,
+              width: decision.width,
+              height: decision.height,
+              ad: retrieveAd(decision)})
+          } else {
+            bid = noBid(bidObj);
+          }
+        } else {
+          bid = noBid(bidObj);
+        }
+        addBidResponse(placementCode, bid);
+      }
+      done()
+    }
+  };
+
+  function retrieveAd(decision) {
+    return decision.contents && decision.contents[0] && decision.contents[0].body + utils.createTrackPixelHtml(decision.impressionUrl);
+  }
+
+  function getSize(sizes) {
+    let width = 'w';
+    let height = 'h';
+    const result = [];
+    sizes.forEach(function(size) {
+      const index = sizeMap.indexOf(size[width] + 'x' + size[height]);
+      if (index >= 0) {
+        result.push(index);
+      }
+    });
+    return result;
+  }
+
+  // Export the `callBids` function, so that Prebid.js can execute
+  // this function when the page asks to send out bid requests.
+  return Object.assign(this, {
+    queueSync: baseAdapter.queueSync,
+    callBids: baseAdapter.callBids,
+    setBidderCode: baseAdapter.setBidderCode,
+    type: TYPE
+  });
+};
+
+ServerBidServerAdapter.createNew = function() {
+  return new ServerBidServerAdapter();
+};
+
+adaptermanager.registerBidAdapter(new ServerBidServerAdapter(), 'serverbidServer');
+
+module.exports = ServerBidServerAdapter;
diff --git a/test/spec/modules/serverbidServerBidAdapter_spec.js b/test/spec/modules/serverbidServerBidAdapter_spec.js
new file mode 100644
index 00000000000..7745d0e407c
--- /dev/null
+++ b/test/spec/modules/serverbidServerBidAdapter_spec.js
@@ -0,0 +1,299 @@
+import { expect } from 'chai';
+import Adapter from 'modules/serverbidServerBidAdapter';
+import * as utils from 'src/utils';
+import { config } from 'src/config';
+import { ajax } from 'src/ajax';
+
+const ENDPOINT = 'https://e.serverbid.com/api/v2';
+
+let CONFIG = {
+  enabled: true,
+  bidders: ['appnexus'],
+  timeout: 1000,
+  adapter: 'serverbidServer',
+  networkId: 9969,
+  siteId: 730181,
+  endpoint: ENDPOINT
+};
+
+let CONFIG_ARG = {
+  s2sConfig: CONFIG
+}
+
+const REQUEST = {
+  'account_id': '1',
+  'tid': '437fbbf5-33f5-487a-8e16-a7112903cfe5',
+  'max_bids': 1,
+  'timeout_millis': 1000,
+  'url': '',
+  'prebid_version': '0.21.0-pre',
+  'ad_units': [
+    {
+      'code': 'div-gpt-ad-1460505748561-0',
+      'sizes': [
+        {
+          'w': 300,
+          'h': 250
+        },
+        {
+          'w': 300,
+          'h': 600
+        }
+      ],
+      'transactionId': '4ef956ad-fd83-406d-bd35-e4bb786ab86c',
+      'bids': [
+        {
+          'bid_id': '123',
+          'bidder': 'appnexus',
+          'params': {
+            'placementId': '10433394',
+            'member': 123
+          }
+        }
+      ]
+    }
+  ]
+};
+
+const BID_REQUESTS = [
+  {
+    'bidderCode': 'appnexus',
+    'auctionId': '173afb6d132ba3',
+    'bidderRequestId': '3d1063078dfcc8',
+    'tid': '437fbbf5-33f5-487a-8e16-a7112903cfe5',
+    'bids': [
+      {
+        'bidder': 'appnexus',
+        'params': {
+          'placementId': '10433394',
+          'member': 123
+        },
+        'bid_id': '123',
+        'adUnitCode': 'div-gpt-ad-1460505748561-0',
+        'transactionId': '4ef956ad-fd83-406d-bd35-e4bb786ab86c',
+        'sizes': [
+          {
+            'w': 300,
+            'h': 250
+          }
+        ],
+        'bidId': '259fb43aaa06c1',
+        'bidderRequestId': '3d1063078dfcc8',
+        'auctionId': '173afb6d132ba3'
+      }
+    ],
+    'auctionStart': 1510852447530,
+    'timeout': 5000,
+    'src': 's2s',
+    'doneCbCallCount': 0
+  }
+];
+
+const RESPONSE = {
+  'user': { 'key': 'ue1-2d33e91b71e74929b4aeecc23f4376f1' },
+  'decisions': {
+    '123': [{
+      'adId': 2364764,
+      'creativeId': 1950991,
+      'flightId': 2788300,
+      'campaignId': 542982,
+      'clickUrl': 'https://e.serverbid.com/r',
+      'impressionUrl': 'https://e.serverbid.com/i.gif',
+      'contents': [{
+        'type': 'html',
+        'body': '<html></html>',
+        'data': {
+          'height': 300,
+          'width': 250,
+          'imageUrl': 'https://static.adzerk.net/Advertisers/b0ab77db8a7848c8b78931aed022a5ef.gif',
+          'fileName': 'b0ab77db8a7848c8b78931aed022a5ef.gif'
+        },
+        'template': 'image'
+      }],
+      'height': 250,
+      'width': 300,
+      'events': [],
+      'pricing': {'price': 0.5, 'clearPrice': 0.5, 'revenue': 0.0005, 'rateType': 2, 'eCPM': 0.5}
+    }],
+  }
+};
+
+const RESPONSE_NO_BID_NO_UNIT = {
+  'user': { 'key': 'ue1-2d33e91b71e74929b4aeecc23f4376f1' },
+  'decisions': {
+    '123': []
+  }
+};
+
+const REQUEST_TWO_UNITS = {
+  'account_id': '1',
+  'tid': '437fbbf5-33f5-487a-8e16-a7112903cfe5',
+  'max_bids': 1,
+  'timeout_millis': 1000,
+  'url': '',
+  'prebid_version': '0.21.0-pre',
+  'ad_units': [
+    {
+      'code': 'div-gpt-ad-1460505748561-0',
+      'sizes': [
+        {
+          'w': 300,
+          'h': 250
+        },
+        {
+          'w': 300,
+          'h': 600
+        }
+      ],
+      'transactionId': '4ef956ad-fd83-406d-bd35-e4bb786ab86c',
+      'bids': [
+        {
+          'bid_id': '123',
+          'bidder': 'appnexus',
+          'params': {
+            'placementId': '10433394',
+            'member': 123
+          }
+        }
+      ]
+    },
+    {
+      'code': 'div-gpt-ad-1460505748561-1',
+      'sizes': [
+        {
+          'w': 300,
+          'h': 250
+        },
+        {
+          'w': 300,
+          'h': 600
+        }
+      ],
+      'transactionId': '4ef956ad-fd83-406d-bd35-e4bb786bb86d',
+      'bids': [
+        {
+          'bid_id': '101111',
+          'bidder': 'appnexus',
+          'params': {
+            'placementId': '10433394',
+            'member': 123
+          }
+        }
+      ]
+    }
+  ]
+};
+
+describe('ServerBid S2S Adapter', () => {
+  let adapter,
+    addBidResponse = sinon.spy(),
+    done = sinon.spy();
+
+  beforeEach(() => adapter = new Adapter());
+
+  afterEach(() => {
+    addBidResponse.reset();
+    done.reset();
+  });
+
+  describe('request function', () => {
+    let xhr;
+    let requests;
+
+    beforeEach(() => {
+      xhr = sinon.useFakeXMLHttpRequest();
+      requests = [];
+      xhr.onCreate = request => requests.push(request);
+    });
+
+    afterEach(() => xhr.restore());
+
+    it('exists and is a function', () => {
+      expect(adapter.callBids).to.exist.and.to.be.a('function');
+    });
+  });
+
+  describe('response handler', () => {
+    let server;
+
+    beforeEach(() => {
+      server = sinon.fakeServer.create();
+      sinon.stub(utils, 'getBidRequest').returns({
+        bidId: '123'
+      });
+    });
+
+    afterEach(() => {
+      server.restore();
+      utils.getBidRequest.restore();
+    });
+
+    it('registers bids', () => {
+      server.respondWith(JSON.stringify(RESPONSE));
+
+      config.setConfig(CONFIG_ARG);
+      adapter.callBids(REQUEST, BID_REQUESTS, addBidResponse, done, ajax);
+      server.respond();
+      sinon.assert.calledOnce(addBidResponse);
+
+      const response = addBidResponse.firstCall.args[1];
+      expect(response).to.have.property('statusMessage', 'Bid available');
+      expect(response).to.have.property('cpm', 0.5);
+      expect(response).to.have.property('adId', '123');
+    });
+
+    it('registers no-bid response when ad unit not set', () => {
+      server.respondWith(JSON.stringify(RESPONSE_NO_BID_NO_UNIT));
+
+      config.setConfig(CONFIG_ARG);
+      adapter.callBids(REQUEST, BID_REQUESTS, addBidResponse, done, ajax);
+      server.respond();
+      sinon.assert.calledOnce(addBidResponse);
+
+      const ad_unit_code = addBidResponse.firstCall.args[0];
+      expect(ad_unit_code).to.equal('div-gpt-ad-1460505748561-0');
+
+      const response = addBidResponse.firstCall.args[1];
+      expect(response).to.have.property('statusMessage', 'Bid returned empty or error response');
+
+      const bid_request_passed = addBidResponse.firstCall.args[1];
+      expect(bid_request_passed).to.have.property('adId', '123');
+    });
+
+    it('registers no-bid response when ad unit is set', () => {
+      server.respondWith(JSON.stringify(RESPONSE_NO_BID_NO_UNIT));
+
+      config.setConfig(CONFIG_ARG);
+      adapter.callBids(REQUEST, BID_REQUESTS, addBidResponse, done, ajax);
+      server.respond();
+      sinon.assert.calledOnce(addBidResponse);
+
+      const ad_unit_code = addBidResponse.firstCall.args[0];
+      expect(ad_unit_code).to.equal('div-gpt-ad-1460505748561-0');
+
+      const response = addBidResponse.firstCall.args[1];
+      expect(response).to.have.property('statusMessage', 'Bid returned empty or error response');
+    });
+
+    it('registers no-bid response when there are less bids than requests', () => {
+      server.respondWith(JSON.stringify(RESPONSE));
+
+      config.setConfig(CONFIG_ARG);
+      adapter.callBids(REQUEST_TWO_UNITS, BID_REQUESTS, addBidResponse, done, ajax);
+      server.respond();
+
+      sinon.assert.calledTwice(addBidResponse);
+
+      expect(addBidResponse.firstCall.args[0]).to.equal('div-gpt-ad-1460505748561-0');
+      expect(addBidResponse.secondCall.args[0]).to.equal('div-gpt-ad-1460505748561-1');
+
+      expect(addBidResponse.firstCall.args[1]).to.have.property('adId', '123');
+      expect(addBidResponse.secondCall.args[1]).to.have.property('adId', '101111');
+
+      expect(addBidResponse.firstCall.args[1])
+        .to.have.property('statusMessage', 'Bid available');
+      expect(addBidResponse.secondCall.args[1])
+        .to.have.property('statusMessage', 'Bid returned empty or error response');
+    });
+  });
+});