diff --git a/modules/tappxBidAdapter.js b/modules/tappxBidAdapter.js
index 1228fbafaad4..1cf5a0f8be7c 100644
--- a/modules/tappxBidAdapter.js
+++ b/modules/tappxBidAdapter.js
@@ -181,6 +181,7 @@ function buildOneRequest(validBidRequests, bidderRequest) {
   const ENDPOINT = utils.deepAccess(validBidRequests, 'params.endpoint');
   const TAPPXKEY = utils.deepAccess(validBidRequests, 'params.tappxkey');
   const BIDFLOOR = utils.deepAccess(validBidRequests, 'params.bidfloor');
+  const BIDEXTRA = utils.deepAccess(validBidRequests, 'params.ext');
   const bannerMediaType = utils.deepAccess(validBidRequests, 'mediaTypes.banner');
   const videoMediaType = utils.deepAccess(validBidRequests, 'mediaTypes.video');
   const { refererInfo } = bidderRequest;
@@ -266,6 +267,7 @@ function buildOneRequest(validBidRequests, bidderRequest) {
   bidder.tappxkey = TAPPXKEY;
   bidder.endpoint = ENDPOINT;
   bidder.host = hostInfo.url;
+  bidder.ext = (typeof BIDEXTRA == 'object') ? BIDEXTRA : undefined;
 
   imp.ext = {};
   imp.ext.bidder = bidder;
@@ -336,7 +338,9 @@ function buildOneRequest(validBidRequests, bidderRequest) {
   payload.params = params;
   payload.regs = regs;
   // < Payload
-
+  utils.logMessage('---------------------');
+  utils.logMessage(JSON.stringify(payload));
+  utils.logMessage('---------------------');
   return {
     method: 'POST',
     url: `https://${HOST}/${ENDPOINT}?type_cnn=${TYPE_CNN}&v=${TAPPX_BIDDER_VERSION}`,
diff --git a/modules/tappxBidAdapter.md b/modules/tappxBidAdapter.md
index e6581a67d063..a07bb2d88d14 100644
--- a/modules/tappxBidAdapter.md
+++ b/modules/tappxBidAdapter.md
@@ -67,4 +67,4 @@ Ads sizes available: [320,50], [300,250], [320,480], [1024,768], [728,90]
             }]
         }
     ];
-```
\ No newline at end of file
+```
diff --git a/test/spec/modules/tappxBidAdapter_spec.js b/test/spec/modules/tappxBidAdapter_spec.js
index 378b391a4eb8..8197c4f44dd9 100644
--- a/test/spec/modules/tappxBidAdapter_spec.js
+++ b/test/spec/modules/tappxBidAdapter_spec.js
@@ -215,6 +215,31 @@ describe('Tappx bid adapter', function () {
       expect(data.imp[0].banner.w).to.be.oneOf([320, 50, 250, 480]);
       expect(data.imp[0].banner.h).to.be.oneOf([320, 50, 250, 480]);
     });
+
+    it('should properly build a ext optional object', function() {
+      let extBidRequest = c_VALIDBIDREQUESTS;
+      extBidRequest[0].params.ext = {'optionalData': '1234'};
+      let extBidderRequest = c_BIDDERREQUEST_B;
+      extBidderRequest.bids[0].ext = {'optionalData': '1234'};
+
+      const request = spec.buildRequests(extBidRequest, extBidderRequest);
+      const data = JSON.parse(request[0].data);
+      expect(data.imp[0].ext.bidder.ext).to.be.an('object');
+      expect(data.imp[0].ext.bidder.ext.optionalData).to.be.equal('1234');
+    });
+
+    it('should ignore ext optional if is not a object', function() {
+      let badExtBidRequest = c_VALIDBIDREQUESTS;
+      badExtBidRequest[0].params.ext = 'stringValue';
+      let badExtBidderRequest = c_BIDDERREQUEST_B;
+      badExtBidderRequest.bids[0].ext = 'stringValue';
+
+      const request = spec.buildRequests(badExtBidRequest, badExtBidderRequest);
+      const data = JSON.parse(request[0].data);
+      expect(data.imp[0].ext.bidder.ext).not.to.be.an('string');
+      expect(data.imp[0].ext.bidder.ext).to.be.an('undefined');
+      expect(data.imp[0].ext.bidder).to.not.have.property('ext')
+    });
   });
 
   /**