diff --git a/api-server/server/boot/certificate.js b/api-server/server/boot/certificate.js
index d5ca128c5c..26aa352a98 100644
--- a/api-server/server/boot/certificate.js
+++ b/api-server/server/boot/certificate.js
@@ -41,6 +41,16 @@ export default function bootCertificate(app) {
   app.use(api);
 }
 
+export function getFallbackFrontEndDate(completedChallenges, completedDate) {
+  var chalIds = [...Object.values(certIds), oldDataVizId];
+
+  const latestCertDate = completedChallenges
+    .filter(chal => chalIds.includes(chal.id))
+    .sort((a, b) => b.completedDate - a.completedDate)[0].completedDate;
+
+  return latestCertDate ? latestCertDate : completedDate;
+}
+
 const noNameMessage = dedent`
   We need your name so we can put it on your certification.
   Add your name to your account settings and click the save button.
@@ -451,13 +461,10 @@ function createShowCert(app) {
 
         // if fullcert is not found, return the latest completedDate
         if (certType === 'isFullStackCert' && !certChallenge) {
-          var chalIds = [...Object.values(certIds), oldDataVizId];
-
-          const latestCertDate = completedChallenges
-            .filter(chal => chalIds.includes(chal.id))
-            .sort((a, b) => a.completedDate < b.completedDate)[0].completedDate;
-
-          completedDate = latestCertDate ? latestCertDate : completedDate;
+          completedDate = getFallbackFrontEndDate(
+            completedChallenges,
+            completedDate
+          );
         }
 
         const { username, name } = user;
diff --git a/api-server/server/boot_tests/certificate.test.js b/api-server/server/boot_tests/certificate.test.js
new file mode 100644
index 0000000000..9d909e821b
--- /dev/null
+++ b/api-server/server/boot_tests/certificate.test.js
@@ -0,0 +1,12 @@
+/* global it expect */
+
+import { getFallbackFrontEndDate } from '../boot/certificate';
+import { fullStackChallenges } from './fixtures';
+
+describe('boot/certificate', () => {
+  describe('getFallbackFrontEndDate', () => {
+    it('should return the date of the latest completed challenge', () => {
+      expect(getFallbackFrontEndDate(fullStackChallenges)).toBe(1685210952511);
+    });
+  });
+});
diff --git a/api-server/server/boot_tests/fixtures.js b/api-server/server/boot_tests/fixtures.js
index 2e60053bfa..5c1b3d939c 100644
--- a/api-server/server/boot_tests/fixtures.js
+++ b/api-server/server/boot_tests/fixtures.js
@@ -178,3 +178,42 @@ export const mockPathMigrationMap = {
   'challenge-one': '/learn/superblock/block/challenge-one',
   'challenge-two': '/learn/superblock/block/challenge-two'
 };
+
+export const fullStackChallenges = [
+  {
+    completedDate: 1585210952511,
+    id: '5a553ca864b52e1d8bceea14',
+    challengeType: 7,
+    files: []
+  },
+  {
+    completedDate: 1585210952511,
+    id: '561add10cb82ac38a17513bc',
+    challengeType: 7,
+    files: []
+  },
+  {
+    completedDate: 1588665778679,
+    id: '561acd10cb82ac38a17513bc',
+    challengeType: 7,
+    files: []
+  },
+  {
+    completedDate: 1685210952511,
+    id: '561abd10cb81ac38a17513bc',
+    challengeType: 7,
+    files: []
+  },
+  {
+    completedDate: 1585210952511,
+    id: '561add10cb82ac38a17523bc',
+    challengeType: 7,
+    files: []
+  },
+  {
+    completedDate: 1588665778679,
+    id: '561add10cb82ac38a17213bc',
+    challengeType: 7,
+    files: []
+  }
+];