diff --git a/modules/zetaBidAdapter.js b/modules/zetaBidAdapter.js
index b168bf581d0..ee5c854df97 100644
--- a/modules/zetaBidAdapter.js
+++ b/modules/zetaBidAdapter.js
@@ -87,14 +87,13 @@ export const spec = {
       badv: params.badv,
       bapp: params.bapp,
       source: params.source ? params.source : {},
-      ext: {
-        definerId: params.definerId
-      }
+      ext: params.ext ? params.ext : {}
     };
 
     payload.device.ua = navigator.userAgent;
     payload.site.page = bidderRequest.refererInfo.referer;
     payload.site.mobile = /(ios|ipod|ipad|iphone|android)/i.test(navigator.userAgent) ? 1 : 0;
+    payload.ext.definerId = params.definerId;
 
     if (params.test) {
       payload.test = params.test;
@@ -113,9 +112,10 @@ export const spec = {
         }
       };
     }
+    const postUrl = params.definerId !== '0' ? ENDPOINT_URL.concat('/', params.definerId) : ENDPOINT_URL;
     return {
       method: 'POST',
-      url: ENDPOINT_URL,
+      url: postUrl,
       data: JSON.stringify(payload),
     };
   },
diff --git a/modules/zetaBidAdapter.md b/modules/zetaBidAdapter.md
index d99846c7822..89a9767d29a 100644
--- a/modules/zetaBidAdapter.md
+++ b/modules/zetaBidAdapter.md
@@ -32,10 +32,10 @@ Module that connects to Zeta's demand sources
                             device: {
                                 ip: '111.222.33.44',
                                 geo: {
-                                    country: "USA"
+                                    country: 'USA'
                                 }
                             },
-                            definerId: 1,
+                            definerId: '0',
                             test: 1
                         }
                     }
diff --git a/test/spec/modules/zetaBidAdapter_spec.js b/test/spec/modules/zetaBidAdapter_spec.js
index b3380ab35db..ccdd5f43cb0 100644
--- a/test/spec/modules/zetaBidAdapter_spec.js
+++ b/test/spec/modules/zetaBidAdapter_spec.js
@@ -10,7 +10,7 @@ describe('Zeta Bid Adapter', function() {
       }
     },
     refererInfo: {
-      referer: 'zetaglobal.com'
+      referer: 'testprebid.com'
     },
     params: {
       placement: 12345,
@@ -24,7 +24,7 @@ describe('Zeta Bid Adapter', function() {
           country: 'USA'
         }
       },
-      definerId: 1,
+      definerId: '0',
       test: 1
     }
   }];