diff --git a/endpoints/cookie_sync.go b/endpoints/cookie_sync.go
index e07c88405a3..4facf172ea5 100644
--- a/endpoints/cookie_sync.go
+++ b/endpoints/cookie_sync.go
@@ -429,16 +429,20 @@ func (c *cookieSyncEndpoint) handleResponse(w http.ResponseWriter, tf usersync.S
 
 	if debug {
 		biddersSeen := make(map[string]struct{})
-		var debugMessages []string
+		var debugInfo []cookieSyncResponseDebug
 		for _, bidderEval := range biddersEvaluated {
+			var debug cookieSyncResponseDebug
+			debug.Bidder = bidderEval.Bidder
 			if bidderEval.Status == usersync.StatusDuplicate && biddersSeen[bidderEval.Bidder] == struct{}{} {
-				debugMessages = append(debugMessages, getDebugMessage(bidderEval.Status)+" synced as "+bidderEval.SyncerKey)
+				debug.Error = getDebugMessage(bidderEval.Status) + " synced as " + bidderEval.SyncerKey
+				debugInfo = append(debugInfo, debug)
 			} else if bidderEval.Status != usersync.StatusOK {
-				debugMessages = append(debugMessages, getDebugMessage(bidderEval.Status)+": "+bidderEval.Bidder)
+				debug.Error = getDebugMessage(bidderEval.Status)
+				debugInfo = append(debugInfo, debug)
 			}
 			biddersSeen[bidderEval.Bidder] = struct{}{}
 		}
-		response.Debug = debugMessages
+		response.Debug = debugInfo
 	}
 
 	c.pbsAnalytics.LogCookieSyncObject(&analytics.CookieSyncObject{
@@ -515,7 +519,7 @@ type cookieSyncRequestFilter struct {
 type cookieSyncResponse struct {
 	Status       string                     `json:"status"`
 	BidderStatus []cookieSyncResponseBidder `json:"bidder_status"`
-	Debug        []string                   `json:"debug"`
+	Debug        []cookieSyncResponseDebug  `json:"debug"`
 }
 
 type cookieSyncResponseBidder struct {
@@ -530,6 +534,11 @@ type cookieSyncResponseSync struct {
 	SupportCORS bool   `json:"supportCORS,omitempty"`
 }
 
+type cookieSyncResponseDebug struct {
+	Bidder string `json:"bidder"`
+	Error  string `json:"error,omitempty"`
+}
+
 type usersyncPrivacyConfig struct {
 	gdprConfig             config.GDPR
 	gdprPermissionsBuilder gdpr.PermissionsBuilder
diff --git a/endpoints/cookie_sync_test.go b/endpoints/cookie_sync_test.go
index 554737b4edf..102ec34fa2b 100644
--- a/endpoints/cookie_sync_test.go
+++ b/endpoints/cookie_sync_test.go
@@ -262,7 +262,7 @@ func TestCookieSyncHandle(t *testing.T) {
 			expectedStatusCode: 200,
 			expectedBody: `{"status":"ok","bidder_status":[` +
 				`{"bidder":"a","no_cookie":true,"usersync":{"url":"aURL","type":"redirect","supportCORS":true}}` +
-				`],"debug":["Already in sync: a"]}` + "\n",
+				`],"debug":[{"bidder":"a","error":"Already in sync"}]}` + "\n",
 			setMetricsExpectations: func(m *metrics.MetricsEngineMock) {
 				m.On("RecordCookieSync", metrics.CookieSyncOK).Once()
 				m.On("RecordSyncerRequest", "aSyncer", metrics.SyncerCookieSyncAlreadySynced).Once()
@@ -1711,7 +1711,7 @@ func TestCookieSyncHandleResponse(t *testing.T) {
 			givenCookieHasSyncs: true,
 			givenDebug:          true,
 			givenSyncersChosen:  []usersync.SyncerChoice{},
-			expectedJSON:        `{"status":"ok","bidder_status":[],"debug":["Already in sync: Bidder1","Unsupported bidder: Bidder2","No sync config: Bidder3","Rejected by privacy: Bidder4","Type not supported: Bidder5","Status blocked by user opt out: Bidder6","Duplicate bidder synced as syncerB"]}` + "\n",
+			expectedJSON:        `{"status":"ok","bidder_status":[],"debug":[{"bidder":"Bidder1","error":"Already in sync"},{"bidder":"Bidder2","error":"Unsupported bidder"},{"bidder":"Bidder3","error":"No sync config"},{"bidder":"Bidder4","error":"Rejected by privacy"},{"bidder":"Bidder5","error":"Type not supported"},{"bidder":"Bidder6","error":"Status blocked by user opt out"},{"bidder":"BidderA","error":"Duplicate bidder synced as syncerB"}]}` + "\n",
 			expectedAnalytics:   analytics.CookieSyncObject{Status: 200, BidderStatus: []*analytics.CookieSyncBidder{}},
 		},
 	}