diff --git a/modules/ixBidAdapter.js b/modules/ixBidAdapter.js
index 4efed90d147..a8ffc4be721 100644
--- a/modules/ixBidAdapter.js
+++ b/modules/ixBidAdapter.js
@@ -38,7 +38,6 @@ const BANNER_TIME_TO_LIVE = 300;
 const VIDEO_TIME_TO_LIVE = 3600; // 1hr
 const NATIVE_TIME_TO_LIVE = 3600; // Since native can have video, use ttl same as video
 const NET_REVENUE = true;
-const MAX_REQUEST_SIZE = 8000;
 const MAX_REQUEST_LIMIT = 4;
 const OUTSTREAM_MINIMUM_PLAYER_SIZE = [144, 144];
 const PRICE_TO_DOLLAR_FACTOR = {
@@ -586,6 +585,12 @@ function buildRequest(validBidRequests, bidderRequest, impressions, version) {
   let userEids = eidInfo.toSend;
   const pageUrl = deepAccess(bidderRequest, 'refererInfo.page');
 
+  let MAX_REQUEST_SIZE = 8000;
+  // Modify request size limit if its FT is enabeld.
+  if (FEATURE_TOGGLES.isFeatureEnabled('pbjs_use_32kb_size_limit')) {
+    MAX_REQUEST_SIZE = 32000
+  }
+
   // RTI ids will be included in the bid request if the function getIdentityInfo() is loaded
   // and if the data for the partner exist
   if (window.headertag && typeof window.headertag.getIdentityInfo === 'function') {
@@ -642,6 +647,9 @@ function buildRequest(validBidRequests, bidderRequest, impressions, version) {
     r.ext.ixdiag.err = cachedErrors;
   }
 
+  // Add number of available imps to ixDiag.
+  r.ext.ixdiag.imps = Object.keys(impressions).length;
+
   // set source.tid to auctionId for outgoing request to Exchange.
   r.source = {
     tid: validBidRequests[0].auctionId,
diff --git a/test/spec/modules/ixBidAdapter_spec.js b/test/spec/modules/ixBidAdapter_spec.js
index a2698fa2cdc..ec749398019 100644
--- a/test/spec/modules/ixBidAdapter_spec.js
+++ b/test/spec/modules/ixBidAdapter_spec.js
@@ -1563,6 +1563,13 @@ describe('IndexexchangeAdapter', function () {
       expect(r.ext.ixdiag.tmax).to.be.undefined
     });
 
+    it('should set ixdiag.imps to number of impressions', function () {
+      const request = spec.buildRequests(DEFAULT_BANNER_VALID_BID)[0];
+      const r = extractPayload(request);
+
+      expect(r.ext.ixdiag.imps).to.equal(1);
+    });
+
     it('should not send information that is not part of openRTB spec v2.5 using ortb2', function () {
       const ortb2 = {
         site: {
@@ -3388,6 +3395,99 @@ describe('IndexexchangeAdapter', function () {
       expect(FEATURE_TOGGLES.isFeatureEnabled('test')).to.be.undefined;
       expect(FEATURE_TOGGLES.featureToggles).to.deep.equal({});
     });
+
+    it('should set request size limit to 32KB when its feature enabled', () => {
+      sandbox.stub(storage, 'localStorageIsEnabled').returns(true);
+      serverResponse.body.ext.features.pbjs_use_32kb_size_limit = {
+        activated: true
+      };
+      FEATURE_TOGGLES.setFeatureToggles(serverResponse);
+      const bid = utils.deepClone(DEFAULT_MULTIFORMAT_VIDEO_VALID_BID[0]);
+      bid.bidderRequestId = Array(10000).join('#');
+
+      expect(spec.isBidRequestValid(bid)).to.be.true;
+      spec.buildRequests([bid], {});
+      const lsData = JSON.parse(storage.getDataFromLocalStorage(LOCAL_STORAGE_FEATURE_TOGGLES_KEY));
+      expect(lsData.features.pbjs_use_32kb_size_limit.activated).to.be.true;
+    });
+
+    it('6 ad units should generate only 2 requests if 32kb size limit FT is enabled', function () {
+      sandbox.stub(storage, 'localStorageIsEnabled').returns(true);
+      serverResponse.body.ext.features.pbjs_use_32kb_size_limit = {
+        activated: true
+      };
+      serverResponse.body.ext.features.pbjs_enable_post = {
+        activated: true
+      };
+      FEATURE_TOGGLES.setFeatureToggles(serverResponse);
+
+      const bid1 = utils.deepClone(DEFAULT_BANNER_VALID_BID[0]);
+      bid1.mediaTypes.banner.sizes = LARGE_SET_OF_SIZES;
+      bid1.params.siteId = '121';
+      bid1.adUnitCode = 'div-gpt-1'
+      bid1.transactionId = 'tr1';
+      bid1.bidId = '2f6g5s5e';
+
+      const bid2 = utils.deepClone(bid1);
+      bid2.transactionId = 'tr2';
+
+      const bid3 = utils.deepClone(bid1);
+      bid3.transactionId = 'tr3';
+
+      const bid4 = utils.deepClone(bid1);
+      bid4.transactionId = 'tr4';
+
+      const bid5 = utils.deepClone(bid1);
+      bid5.transactionId = 'tr5';
+
+      const bid6 = utils.deepClone(bid1);
+      bid6.transactionId = 'tr6';
+
+      const requests = spec.buildRequests([bid1, bid2, bid3, bid4, bid5, bid6], DEFAULT_OPTION);
+
+      expect(requests).to.be.an('array');
+      // 32KB size limit causes only 2 requests to get generated.
+      expect(requests).to.have.lengthOf(2);
+      for (let request of requests) {
+        expect(request.method).to.equal('POST');
+      }
+    });
+
+    it('4 ad units should generate only 1 requests if 32kb size limit FT is enabled', function () {
+      sandbox.stub(storage, 'localStorageIsEnabled').returns(true);
+      serverResponse.body.ext.features.pbjs_use_32kb_size_limit = {
+        activated: true
+      };
+      serverResponse.body.ext.features.pbjs_enable_post = {
+        activated: true
+      };
+      FEATURE_TOGGLES.setFeatureToggles(serverResponse);
+
+      const bid1 = utils.deepClone(DEFAULT_BANNER_VALID_BID[0]);
+      bid1.mediaTypes.banner.sizes = LARGE_SET_OF_SIZES;
+      bid1.params.siteId = '121';
+      bid1.adUnitCode = 'div-gpt-1'
+      bid1.transactionId = 'tr1';
+      bid1.bidId = '2f6g5s5e';
+
+      const bid2 = utils.deepClone(bid1);
+      bid2.transactionId = 'tr2';
+
+      const bid3 = utils.deepClone(bid1);
+      bid3.transactionId = 'tr3';
+
+      const bid4 = utils.deepClone(bid1);
+      bid4.transactionId = 'tr4';
+
+      const requests = spec.buildRequests([bid1, bid2, bid3, bid4], DEFAULT_OPTION);
+
+      expect(requests).to.be.an('array');
+      // 32KB size limit causes only 1 requests to get generated.
+      expect(requests).to.have.lengthOf(1);
+      for (let request of requests) {
+        expect(request.method).to.equal('POST');
+      }
+    });
   });
 
   describe('LocalStorage error codes', () => {