diff --git a/adapters/synacormedia/params_test.go b/adapters/synacormedia/params_test.go
index ffd891f4e84..a216818e382 100644
--- a/adapters/synacormedia/params_test.go
+++ b/adapters/synacormedia/params_test.go
@@ -40,9 +40,9 @@ func TestInvalidParams(t *testing.T) {
 }
 
 var validParams = []string{
-	`{"seatId": "123"}`,
+	`{"seatId": "123", "tagId":"234"}`,
 }
 
 var invalidParams = []string{
-	`{"seatId": 123}`,
+	`{"seatId": 123, "tagId":234}`,
 }
diff --git a/adapters/synacormedia/synacormedia.go b/adapters/synacormedia/synacormedia.go
index ccb2798f8cf..2d913f026b4 100644
--- a/adapters/synacormedia/synacormedia.go
+++ b/adapters/synacormedia/synacormedia.go
@@ -20,6 +20,7 @@ type SynacorMediaAdapter struct {
 
 type SyncEndpointTemplateParams struct {
 	SeatId string
+	TagId  string
 }
 
 type ReqExt struct {
@@ -55,14 +56,23 @@ func (a *SynacorMediaAdapter) makeRequest(request *openrtb.BidRequest) (*adapter
 	var firstExtImp *openrtb_ext.ExtImpSynacormedia = nil
 
 	for _, imp := range request.Imp {
-		validImp, err := getExtImpObj(&imp)
+		validExtImpObj, err := getExtImpObj(&imp) // getExtImpObj returns {seatId:"", tagId:""}
 		if err != nil {
 			errs = append(errs, err)
 			continue
 		}
+		// if the bid request is missing seatId or TagId then ignore it
+		if validExtImpObj.SeatId == "" || validExtImpObj.TagId == "" {
+			errs = append(errs, &errortypes.BadServerResponse{
+				Message: fmt.Sprintf("Invalid Impression"),
+			})
+			continue
+		}
+		// right here is where we need to take out the tagId and then add it to imp
+		imp.TagID = validExtImpObj.TagId
 		validImps = append(validImps, imp)
 		if firstExtImp == nil {
-			firstExtImp = validImp
+			firstExtImp = validExtImpObj
 		}
 	}
 
@@ -72,11 +82,12 @@ func (a *SynacorMediaAdapter) makeRequest(request *openrtb.BidRequest) (*adapter
 
 	var err error
 
-	if firstExtImp == nil || firstExtImp.SeatId == "" {
+	if firstExtImp == nil || firstExtImp.SeatId == "" || firstExtImp.TagId == "" {
 		return nil, append(errs, &errortypes.BadServerResponse{
-			Message: fmt.Sprintf("Impression missing seat id"),
+			Message: fmt.Sprintf("Invalid Impression"),
 		})
 	}
+	// this is where the empty seatId is filled
 	re = &ReqExt{SeatId: firstExtImp.SeatId}
 
 	// create JSON Request Body
diff --git a/adapters/synacormedia/synacormediatest/exemplary/simple-banner.json b/adapters/synacormedia/synacormediatest/exemplary/simple-banner.json
index 013891b6fa8..944e6e549ab 100644
--- a/adapters/synacormedia/synacormediatest/exemplary/simple-banner.json
+++ b/adapters/synacormedia/synacormediatest/exemplary/simple-banner.json
@@ -14,7 +14,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -24,15 +25,16 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "banner": {
                 "format": [
                   {"w":300,"h":250}
@@ -40,7 +42,8 @@
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/exemplary/simple-video.json b/adapters/synacormedia/synacormediatest/exemplary/simple-video.json
index f12556105db..2cddd5220f9 100644
--- a/adapters/synacormedia/synacormediatest/exemplary/simple-video.json
+++ b/adapters/synacormedia/synacormediatest/exemplary/simple-video.json
@@ -10,7 +10,6 @@
     "imp": [
       {
         "id": "i3",
-        "tagid": "3020",
         "video": {
           "w": 300,
           "h": 250,
@@ -21,8 +20,9 @@
         },
         "metric": [],
         "ext": {
-          "bidder":{
-            "seatId":"1927"
+          "bidder": {
+            "seatId":"prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -31,7 +31,7 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "1",
           "site": {
@@ -40,12 +40,12 @@
             "publisher": {}
           },
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id": "i3",
-              "tagid": "3020",
+              "tagid": "demo1",
               "video": {
                 "w": 300,
                 "h": 250,
@@ -56,7 +56,8 @@
               },
               "ext": {
                 "bidder":{
-                  "seatId":"1927"
+                  "seatId":"prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/params/banner.json b/adapters/synacormedia/synacormediatest/params/banner.json
index d6f4e7e9641..bb55ddfc48c 100644
--- a/adapters/synacormedia/synacormediatest/params/banner.json
+++ b/adapters/synacormedia/synacormediatest/params/banner.json
@@ -1,3 +1,4 @@
 {
-  "seatId": "123"
+  "seatId": "123",
+  "tagId": "234"
 }
diff --git a/adapters/synacormedia/synacormediatest/params/video.json b/adapters/synacormedia/synacormediatest/params/video.json
index d6f4e7e9641..bb55ddfc48c 100644
--- a/adapters/synacormedia/synacormediatest/params/video.json
+++ b/adapters/synacormedia/synacormediatest/params/video.json
@@ -1,3 +1,4 @@
 {
-  "seatId": "123"
+  "seatId": "123",
+  "tagId": "234"
 }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/audio_response.json b/adapters/synacormedia/synacormediatest/supplemental/audio_response.json
index 172a81efa85..752d610aa72 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/audio_response.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/audio_response.json
@@ -9,7 +9,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -19,21 +20,23 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "audio": {
                 "mimes": ["video/mp4"]
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/bad_response.json b/adapters/synacormedia/synacormediatest/supplemental/bad_response.json
index 0893598bd1d..8e8b9a4d944 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/bad_response.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/bad_response.json
@@ -18,7 +18,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -28,15 +29,16 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "banner": {
                 "format": [
                   {"w":300,"h":250},
@@ -45,7 +47,8 @@
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/bad_seat_id.json b/adapters/synacormedia/synacormediatest/supplemental/bad_seat_id.json
index bb144f1c6db..00dd2c23707 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/bad_seat_id.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/bad_seat_id.json
@@ -14,7 +14,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": 1927
+            "seatId": 1927,
+            "tagId": "demo1"
           }
         }
       }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/missing_seat_id.json b/adapters/synacormedia/synacormediatest/supplemental/missing_seat_id.json
index a085b6e64f9..b85b88e4189 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/missing_seat_id.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/missing_seat_id.json
@@ -14,6 +14,7 @@
         },
         "ext": {
           "bidder": {
+            "tagId": "demo1"
           }
         }
       }
@@ -22,7 +23,7 @@
 
   "expectedMakeRequestsErrors": [
     {
-      "value": "Impression missing seat id",
+      "value": "Invalid Impression",
       "comparison": "literal"
     }
   ]
diff --git a/adapters/synacormedia/synacormediatest/supplemental/missing_tag_id.json b/adapters/synacormedia/synacormediatest/supplemental/missing_tag_id.json
new file mode 100644
index 00000000000..2e1ef6ada65
--- /dev/null
+++ b/adapters/synacormedia/synacormediatest/supplemental/missing_tag_id.json
@@ -0,0 +1,30 @@
+{
+  "mockBidRequest": {
+    "id": "test-request-id",
+    "imp": [
+      {
+        "id": "test-imp-id",
+        "banner": {
+          "format": [
+            {
+              "w": 300,
+              "h": 250
+            }
+          ]
+        },
+        "ext": {
+          "bidder": {
+            "seatId": "prebid"
+          }
+        }
+      }
+    ]
+  },
+
+  "expectedMakeRequestsErrors": [
+    {
+      "value": "Invalid Impression",
+      "comparison": "literal"
+    }
+  ]
+}
diff --git a/adapters/synacormedia/synacormediatest/supplemental/native_response.json b/adapters/synacormedia/synacormediatest/supplemental/native_response.json
index 89742d6e0df..1428ac1ccd3 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/native_response.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/native_response.json
@@ -9,7 +9,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -19,21 +20,23 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "native": {
                 "request": ""
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/one_bad_ext.json b/adapters/synacormedia/synacormediatest/supplemental/one_bad_ext.json
new file mode 100644
index 00000000000..5749aadba98
--- /dev/null
+++ b/adapters/synacormedia/synacormediatest/supplemental/one_bad_ext.json
@@ -0,0 +1,136 @@
+{
+  "mockBidRequest": {
+    "id": "test-request-id",
+    "imp": [
+      {
+        "id": "test-imp-bad",
+        "banner": {
+          "format": [
+            {
+              "w": 300,
+              "h": 250
+            }
+          ]
+        },
+        "ext": {
+          "bidder": {
+            "seatId": "",
+            "tagId": ""
+          }
+        }
+      },
+      {
+        "id": "test-imp-id",
+        "banner": {
+          "format": [
+            {
+              "w": 300,
+              "h": 250
+            }
+          ]
+        },
+        "ext": {
+          "bidder": {
+            "seatId": "prebid",
+            "tagId": "demo1"
+          }
+        }
+      }
+    ]
+  },
+
+  "httpCalls": [
+    {
+      "expectedRequest": {
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
+        "body": {
+          "id": "test-request-id",
+          "ext": {
+            "seatId": "prebid"
+          },
+          "imp": [
+            {
+              "id":"test-imp-id",
+              "tagid": "demo1",
+              "banner": {
+                "format": [
+                  {"w":300,"h":250}
+                ]
+              },
+              "ext": {
+                "bidder": {
+                  "seatId": "prebid",
+                  "tagId": "demo1"
+                }
+              }
+            }
+          ]
+        }
+      },
+      "mockResponse": {
+        "status": 200,
+        "body": {
+          "id": "1",
+          "seatbid": [
+            {
+              "bid": [
+                {
+                  "id": "test-request-id",
+                  "impid": "test-imp-id",
+                  "price": 2.69,
+                  "adomain": [
+                    "psacentral.org"
+                  ],
+                  "cid": "mock-crid",
+                  "crid": "mock-cid",
+                  "ext": {
+                    "prebid": {
+                      "type": "banner"
+                    }
+                  }
+                }
+              ],
+              "seat": "synacormedia"
+            }
+          ],
+          "ext": {
+            "responsetimemillis": {
+              "synacormedia": 339
+            }
+          }
+        }
+      }
+    }
+  ],
+  "expectedBidResponses": [
+    {
+      "currency": "USD",
+      "bids": [
+        {
+          "bid": {
+            "adomain": [
+              "psacentral.org"
+            ],
+            "cid": "mock-crid",
+            "crid": "mock-cid",
+            "ext": {
+              "prebid": {
+                "type": "banner"
+              }
+            },
+            "id": "test-request-id",
+            "impid": "test-imp-id",
+            "price": 2.69
+          },
+          "type": "banner"
+        }
+      ]
+    }
+  ],
+  "expectedMakeRequestsErrors": [
+    {
+      "value": "Invalid Impression",
+      "comparison": "literal"
+    }
+  ]
+}
diff --git a/adapters/synacormedia/synacormediatest/supplemental/status_204.json b/adapters/synacormedia/synacormediatest/supplemental/status_204.json
index f53ff1ec918..76f97f9cdfa 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/status_204.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/status_204.json
@@ -18,7 +18,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -28,15 +29,16 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "banner": {
                 "format": [
                   {"w":300,"h":250},
@@ -45,7 +47,8 @@
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/status_400.json b/adapters/synacormedia/synacormediatest/supplemental/status_400.json
index a0667658e1d..1bb2cf6fa45 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/status_400.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/status_400.json
@@ -18,7 +18,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -28,15 +29,16 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "banner": {
                 "format": [
                   {"w":300,"h":250},
@@ -45,7 +47,8 @@
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/adapters/synacormedia/synacormediatest/supplemental/status_500.json b/adapters/synacormedia/synacormediatest/supplemental/status_500.json
index 125829c2328..37ca398e59e 100644
--- a/adapters/synacormedia/synacormediatest/supplemental/status_500.json
+++ b/adapters/synacormedia/synacormediatest/supplemental/status_500.json
@@ -18,7 +18,8 @@
         },
         "ext": {
           "bidder": {
-            "seatId": "1927"
+            "seatId": "prebid",
+            "tagId": "demo1"
           }
         }
       }
@@ -28,15 +29,16 @@
   "httpCalls": [
     {
       "expectedRequest": {
-        "uri": "http://1927.technoratimedia.com/openrtb/bids/1927",
+        "uri": "http://prebid.technoratimedia.com/openrtb/bids/prebid",
         "body": {
           "id": "test-request-id",
           "ext": {
-            "seatId": "1927"
+            "seatId": "prebid"
           },
           "imp": [
             {
               "id":"test-imp-id",
+              "tagid": "demo1",
               "banner": {
                 "format": [
                   {"w":300,"h":250},
@@ -45,7 +47,8 @@
               },
               "ext": {
                 "bidder": {
-                  "seatId": "1927"
+                  "seatId": "prebid",
+                  "tagId": "demo1"
                 }
               }
             }
diff --git a/openrtb_ext/imp_synacormedia.go b/openrtb_ext/imp_synacormedia.go
index 1b044ceaa9c..af48c7dfd01 100644
--- a/openrtb_ext/imp_synacormedia.go
+++ b/openrtb_ext/imp_synacormedia.go
@@ -3,4 +3,5 @@ package openrtb_ext
 // ExtImpSynacormedia defines the contract for bidrequest.imp[i].ext.synacormedia
 type ExtImpSynacormedia struct {
 	SeatId string `json:"seatId"`
+	TagId  string `json:"tagId"`
 }
diff --git a/static/bidder-params/synacormedia.json b/static/bidder-params/synacormedia.json
index b2dff8faca1..8c74ada2e85 100644
--- a/static/bidder-params/synacormedia.json
+++ b/static/bidder-params/synacormedia.json
@@ -8,6 +8,10 @@
     "seatId": {
       "type": "string",
       "description": "The seat id."
+    },
+    "tagId": {
+      "type": "string",
+      "description": "The tag id."
     }
   },