diff --git a/adapters/kobler/kobler.go b/adapters/kobler/kobler.go
index fe422b0ff2..2468497377 100644
--- a/adapters/kobler/kobler.go
+++ b/adapters/kobler/kobler.go
@@ -37,6 +37,8 @@ func (a adapter) MakeRequests(request *openrtb2.BidRequest, reqInfo *adapters.Ex
 	var requestData []*adapters.RequestData
 	var errors []error
 
+	testMode := false
+
 	if !sliceutil.Contains(request.Cur, supportedCurrency) {
 		request.Cur = append(request.Cur, supportedCurrency)
 	}
@@ -46,6 +48,29 @@ func (a adapter) MakeRequests(request *openrtb2.BidRequest, reqInfo *adapters.Ex
 			errors = append(errors, err)
 			return nil, errors
 		}
+
+		// Check the first Imp for test mode, which decides the endpoint.
+		if i == 0 && request.Imp[i].Ext != nil {
+			var bidderExt adapters.ExtImpBidder
+			if err := jsonutil.Unmarshal(request.Imp[i].Ext, &bidderExt); err != nil {
+				errors = append(errors, &errortypes.BadInput{
+					Message: "Error parsing bidderExt object",
+				})
+				continue
+			}
+
+			var impExt openrtb_ext.ExtImpKobler
+			if err := jsonutil.Unmarshal(bidderExt.Bidder, &impExt); err != nil {
+				errors = append(errors, &errortypes.BadInput{
+					Message: "Error parsing impExt object",
+				})
+				continue
+			}
+
+			if impExt.Test != nil {
+				testMode = *impExt.Test
+			}
+		}
 	}
 
 	requestJSON, err := jsonutil.Marshal(request)
@@ -54,12 +79,19 @@ func (a adapter) MakeRequests(request *openrtb2.BidRequest, reqInfo *adapters.Ex
 		return nil, errors
 	}
 
+	// Use a separate endpoint for testing purposes in the DEV environment.
+	// Required due to Kobler's internal test campaign setup.
+	endpoint := a.endpoint
+	if testMode {
+		endpoint = a.devEndpoint
+	}
+
 	headers := http.Header{}
 	headers.Add("Content-Type", "application/json;charset=utf-8")
 
 	requestData = append(requestData, &adapters.RequestData{
 		Method:  "POST",
-		Uri:     a.getEndpoint(request),
+		Uri:     endpoint,
 		Body:    requestJSON,
 		ImpIDs:  openrtb_ext.GetImpIDs(request.Imp),
 		Headers: headers,
@@ -99,16 +131,6 @@ func (a adapter) MakeBids(request *openrtb2.BidRequest, requestData *adapters.Re
 	return bidResponse, nil
 }
 
-// Use a separate endpoint for testing purposes in the DEV environment.
-// Required due to Kobler's internal test campaign setup.
-func (a adapter) getEndpoint(request *openrtb2.BidRequest) string {
-	if request.Test == 1 {
-		return a.devEndpoint
-	}
-
-	return a.endpoint
-}
-
 func getMediaTypeForBid(bid openrtb2.Bid) openrtb_ext.BidType {
 	if bid.Ext != nil {
 		var bidExt openrtb_ext.ExtBid
diff --git a/adapters/kobler/koblertest/supplemental/correct-endpoint-when-testing.json b/adapters/kobler/koblertest/supplemental/correct-endpoint-when-testing.json
index ea9eabdbb7..53c546d86f 100644
--- a/adapters/kobler/koblertest/supplemental/correct-endpoint-when-testing.json
+++ b/adapters/kobler/koblertest/supplemental/correct-endpoint-when-testing.json
@@ -1,7 +1,6 @@
 {
   "mockBidRequest": {
     "id": "test-request-id",
-    "test": 1,
     "device": {
       "devicetype": 2
     },
@@ -23,6 +22,11 @@
               "h": 100
             }
           ]
+        },
+        "ext": {
+          "bidder": {
+            "test": true
+          }
         }
       }
     ]
@@ -33,7 +37,6 @@
         "uri": "https://bid-service.dev.essrtb.com/bid/prebid_server_rtb_call",
         "body": {
           "id": "test-request-id",
-          "test": 1,
           "device": {
             "devicetype": 2
           },
@@ -55,6 +58,11 @@
                     "h": 100
                   }
                 ]
+              },
+              "ext": {
+                "bidder": {
+                  "test": true
+                }
               }
             }
           ],
diff --git a/openrtb_ext/imp_kobler.go b/openrtb_ext/imp_kobler.go
new file mode 100644
index 0000000000..c02393c803
--- /dev/null
+++ b/openrtb_ext/imp_kobler.go
@@ -0,0 +1,5 @@
+package openrtb_ext
+
+type ExtImpKobler struct {
+	Test *bool `json:"test"`
+}
diff --git a/static/bidder-params/kobler.json b/static/bidder-params/kobler.json
index c4b8de72df..7e85601bfe 100644
--- a/static/bidder-params/kobler.json
+++ b/static/bidder-params/kobler.json
@@ -4,5 +4,10 @@
   "description": "A schema which validates params accepted by the Kobler adapter",
   "type": "object",
 
-  "properties": {}
+  "properties": {
+    "test": {
+      "type": "boolean",
+      "description": "Whether the request is for testing only. When multiple ad units are submitted together, it is enough to set this parameter on the first one."
+    }
+  }
 }