diff --git a/modules/sonobiBidAdapter.js b/modules/sonobiBidAdapter.js
index a55992cec22..0e4bfb37829 100644
--- a/modules/sonobiBidAdapter.js
+++ b/modules/sonobiBidAdapter.js
@@ -1,10 +1,9 @@
 import { registerBidder } from '../src/adapters/bidderFactory.js';
-import { parseSizesInput, logError, generateUUID, isEmpty, deepAccess, logWarn, logMessage } from '../src/utils.js';
+import { parseSizesInput, logError, generateUUID, isEmpty, deepAccess, logWarn, logMessage, deepClone } from '../src/utils.js';
 import { BANNER, VIDEO } from '../src/mediaTypes.js';
 import { config } from '../src/config.js';
 import { Renderer } from '../src/Renderer.js';
 import { userSync } from '../src/userSync.js';
-
 const BIDDER_CODE = 'sonobi';
 const STR_ENDPOINT = 'https://apex.go.sonobi.com/trinity.json';
 const PAGEVIEW_ID = generateUUID();
@@ -117,7 +116,18 @@ export const spec = {
       payload.schain = JSON.stringify(validBidRequests[0].schain)
     }
     if (deepAccess(validBidRequests[0], 'userId') && Object.keys(validBidRequests[0].userId).length > 0) {
-      payload.userid = JSON.stringify(validBidRequests[0].userId);
+      const userIds = deepClone(validBidRequests[0].userId);
+
+      if (userIds.id5id) {
+        userIds.id5id = deepAccess(userIds, 'id5id.uid');
+      }
+
+      payload.userid = JSON.stringify(userIds);
+    }
+
+    const eids = deepAccess(validBidRequests[0], 'userIdAsEids');
+    if (Array.isArray(eids) && eids.length > 0) {
+      payload.eids = JSON.stringify(eids);
     }
 
     let keywords = validBidRequests[0].params.keywords; // a CSV of keywords
diff --git a/test/spec/modules/sonobiBidAdapter_spec.js b/test/spec/modules/sonobiBidAdapter_spec.js
index 52821072a21..d1ac200394c 100644
--- a/test/spec/modules/sonobiBidAdapter_spec.js
+++ b/test/spec/modules/sonobiBidAdapter_spec.js
@@ -414,15 +414,92 @@ describe('SonobiBidAdapter', function () {
       expect(JSON.parse(bidRequests.data.schain)).to.deep.equal(bidRequest[0].schain)
     });
 
+    it('should return a properly formatted request with eids as a JSON-encoded set of eids', function () {
+      bidRequest[0].userIdAsEids = [
+        {
+          'source': 'pubcid.org',
+          'uids': [
+            {
+              'id': '97b1ff9b-6bf1-41fc-95de-acfd33dbb95a',
+              'atype': 1
+            }
+          ]
+        },
+        {
+          'source': 'sharedid.org',
+          'uids': [
+            {
+              'id': '01ERJ6W40EXJZNQJVJZWASEG7J',
+              'atype': 1,
+              'ext': {
+                'third': '01ERJ6W40EXJZNQJVJZWASEG7J'
+              }
+            }
+          ]
+        }
+      ];
+      bidRequest[1].userIdAsEids = [
+        {
+          'source': 'pubcid.org',
+          'uids': [
+            {
+              'id': '97b1ff9b-6bf1-41fc-95de-acfd33dbb95a',
+              'atype': 1
+            }
+          ]
+        },
+        {
+          'source': 'sharedid.org',
+          'uids': [
+            {
+              'id': '01ERJ6W40EXJZNQJVJZWASEG7J',
+              'atype': 1,
+              'ext': {
+                'third': '01ERJ6W40EXJZNQJVJZWASEG7J'
+              }
+            }
+          ]
+        }
+      ];
+      const bidRequests = spec.buildRequests(bidRequest, bidderRequests);
+      expect(bidRequests.url).to.equal('https://apex.go.sonobi.com/trinity.json');
+      expect(bidRequests.method).to.equal('GET');
+      expect(bidRequests.data.ref).not.to.be.empty;
+      expect(bidRequests.data.s).not.to.be.empty;
+      expect(JSON.parse(bidRequests.data.eids)).to.eql([
+        {
+          'source': 'pubcid.org',
+          'uids': [
+            {
+              'id': '97b1ff9b-6bf1-41fc-95de-acfd33dbb95a',
+              'atype': 1
+            }
+          ]
+        },
+        {
+          'source': 'sharedid.org',
+          'uids': [
+            {
+              'id': '01ERJ6W40EXJZNQJVJZWASEG7J',
+              'atype': 1,
+              'ext': {
+                'third': '01ERJ6W40EXJZNQJVJZWASEG7J'
+              }
+            }
+          ]
+        }
+      ]);
+    });
+
     it('should return a properly formatted request with userid as a JSON-encoded set of User ID results', function () {
-      bidRequest[0].userId = {'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101'};
-      bidRequest[1].userId = {'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101'};
+      bidRequest[0].userId = {'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101', 'id5id': {'uid': 'ID5-ZHMOrVeUVTUKgrZ-a2YGxeh5eS_pLzHCQGYOEAiTBQ', 'ext': {'linkType': 2}}};
+      bidRequest[1].userId = {'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101', 'id5id': {'uid': 'ID5-ZHMOrVeUVTUKgrZ-a2YGxeh5eS_pLzHCQGYOEAiTBQ', 'ext': {'linkType': 2}}};
       const bidRequests = spec.buildRequests(bidRequest, bidderRequests);
       expect(bidRequests.url).to.equal('https://apex.go.sonobi.com/trinity.json');
       expect(bidRequests.method).to.equal('GET');
       expect(bidRequests.data.ref).not.to.be.empty;
       expect(bidRequests.data.s).not.to.be.empty;
-      expect(JSON.parse(bidRequests.data.userid)).to.eql({'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101'});
+      expect(JSON.parse(bidRequests.data.userid)).to.eql({'pubcid': 'abcd-efg-0101', 'tdid': 'td-abcd-efg-0101', 'id5id': 'ID5-ZHMOrVeUVTUKgrZ-a2YGxeh5eS_pLzHCQGYOEAiTBQ'});
     });
 
     it('should return a properly formatted request with userid omitted if there are no userIds', function () {
@@ -469,7 +546,7 @@ describe('SonobiBidAdapter', function () {
       ];
       const bidRequests = spec.buildRequests(bRequest, bidderRequests);
       expect(bidRequests.url).to.equal('https://iad-2-apex.go.sonobi.com/trinity.json');
-    })
+    });
   });
 
   describe('.interpretResponse', function () {