diff --git a/api/db/database-builder/factory/build-knowledge-element-snapshot.js b/api/db/database-builder/factory/build-knowledge-element-snapshot.js
index 1a3888501e8..24c1529f4f2 100644
--- a/api/db/database-builder/factory/build-knowledge-element-snapshot.js
+++ b/api/db/database-builder/factory/build-knowledge-element-snapshot.js
@@ -1,5 +1,6 @@
 import _ from 'lodash';
 
+import { KnowledgeElementCollection } from '../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { databaseBuffer } from '../database-buffer.js';
 import { buildKnowledgeElement } from './build-knowledge-element.js';
 import { buildUser } from './build-user.js';
@@ -17,7 +18,7 @@ const buildKnowledgeElementSnapshot = function ({
     const knowledgeElements = [];
     knowledgeElements.push(buildKnowledgeElement({ userId, createdAt: dateMinusOneDay }));
     knowledgeElements.push(buildKnowledgeElement({ userId, createdAt: dateMinusOneDay }));
-    snapshot = JSON.stringify(knowledgeElements);
+    snapshot = new KnowledgeElementCollection(knowledgeElements).toSnapshot();
   }
 
   const values = {
diff --git a/api/db/seeds/data/common/tooling/campaign-tooling.js b/api/db/seeds/data/common/tooling/campaign-tooling.js
index 68f574b54c9..8844119abeb 100644
--- a/api/db/seeds/data/common/tooling/campaign-tooling.js
+++ b/api/db/seeds/data/common/tooling/campaign-tooling.js
@@ -5,6 +5,7 @@ import {
   CampaignExternalIdTypes,
   CampaignParticipationStatuses,
 } from '../../../../../src/prescription/shared/domain/constants.js';
+import { KnowledgeElementCollection } from '../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { Assessment, KnowledgeElement } from '../../../../../src/shared/domain/models/index.js';
 import { getPlacementProfile } from '../../../../../src/shared/domain/services/placement-profile-service.js';
 import { FEATURE_CAMPAIGN_EXTERNAL_ID } from '../constants.js';
@@ -240,7 +241,7 @@ async function createAssessmentCampaign({
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify(keDataForSnapshot),
+          snapshot: new KnowledgeElementCollection(keDataForSnapshot).toSnapshot(),
           campaignParticipationId,
         });
 
@@ -404,7 +405,7 @@ async function createProfilesCollectionCampaign({
       databaseBuilder.factory.buildKnowledgeElementSnapshot({
         userId,
         snappedAt: sharedAt,
-        snapshot: JSON.stringify(keDataForSnapshot),
+        snapshot: new KnowledgeElementCollection(keDataForSnapshot).toSnapshot(),
         campaignParticipationId,
       });
 
diff --git a/api/db/seeds/data/common/tooling/profile-tooling.js b/api/db/seeds/data/common/tooling/profile-tooling.js
index 9e1daa38097..9f0d2ca0378 100644
--- a/api/db/seeds/data/common/tooling/profile-tooling.js
+++ b/api/db/seeds/data/common/tooling/profile-tooling.js
@@ -23,11 +23,11 @@ export {
  * @returns {Promise<void>}
  */
 async function createCertifiableProfile({ databaseBuilder, userId }) {
-  const answersAndKnowledgeElementsCollection = await getAnswersAndKnowledgeElementsForBeginnerProfile();
+  const answersAndKnowledgeElementCollection = await getAnswersAndKnowledgeElementsForBeginnerProfile();
   _makeUserReachPixScoreForCompetences({
     databaseBuilder,
     userId,
-    answersAndKnowledgeElementsCollection,
+    answersAndKnowledgeElementCollection,
   });
 
   await databaseBuilder.commit();
@@ -40,12 +40,12 @@ async function createCertifiableProfile({ databaseBuilder, userId }) {
  * @returns {Promise<void>}
  */
 async function createPerfectProfile({ databaseBuilder, userId }) {
-  const answersAndKnowledgeElementsCollection = await getAnswersAndKnowledgeElementsForPerfectProfile();
+  const answersAndKnowledgeElementCollection = await getAnswersAndKnowledgeElementsForPerfectProfile();
 
   _makeUserReachPixScoreForCompetences({
     databaseBuilder,
     userId,
-    answersAndKnowledgeElementsCollection,
+    answersAndKnowledgeElementCollection,
   });
 
   await databaseBuilder.commit();
@@ -59,7 +59,7 @@ async function getAnswersAndKnowledgeElementsForBeginnerProfile() {
 
     await _getAnswersAndKnowledgeElementsForProfile({
       competences: fiveRandomCompetences,
-      answersAndKnowledgeElementsCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_BEGINNER_PROFILE,
+      answersAndKnowledgeElementCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_BEGINNER_PROFILE,
       pixScoreByCompetence: PIX_COUNT_BY_LEVEL,
     });
   }
@@ -75,7 +75,7 @@ async function getAnswersAndKnowledgeElementsForIntermediateProfile() {
 
     await _getAnswersAndKnowledgeElementsForProfile({
       competences: eightRandomCompetences,
-      answersAndKnowledgeElementsCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_INTERMEDIATE_PROFILE,
+      answersAndKnowledgeElementCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_INTERMEDIATE_PROFILE,
       pixScoreByCompetence: PIX_COUNT_BY_LEVEL * 3,
     });
   }
@@ -91,7 +91,7 @@ async function getAnswersAndKnowledgeElementsForAdvancedProfile() {
 
     await _getAnswersAndKnowledgeElementsForProfile({
       competences: twelveRandomCompetences,
-      answersAndKnowledgeElementsCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_ADVANCED_PROFILE,
+      answersAndKnowledgeElementCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_ADVANCED_PROFILE,
       pixScoreByCompetence: PIX_COUNT_BY_LEVEL * 4,
     });
   }
@@ -106,7 +106,7 @@ async function getAnswersAndKnowledgeElementsForPerfectProfile() {
 
     await _getAnswersAndKnowledgeElementsForProfile({
       competences: pixCompetences,
-      answersAndKnowledgeElementsCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_PERFECT_PROFILE,
+      answersAndKnowledgeElementCollection: ANSWERS_AND_KNOWLEDGE_ELEMENTS_FOR_PERFECT_PROFILE,
       pixScoreByCompetence: UNREACHABLE_PIX_SCORE,
     });
   }
@@ -117,7 +117,7 @@ async function getAnswersAndKnowledgeElementsForPerfectProfile() {
 async function _getAnswersAndKnowledgeElementsForProfile({
   competences,
   pixScoreByCompetence,
-  answersAndKnowledgeElementsCollection,
+  answersAndKnowledgeElementCollection,
 }) {
   for (const competence of competences) {
     const skills = await learningContent.findActiveSkillsByCompetenceId(competence.id);
@@ -147,7 +147,7 @@ async function _getAnswersAndKnowledgeElementsForProfile({
         earnedPix: skill.pixValue,
         competenceId: skill.competenceId,
       };
-      answersAndKnowledgeElementsCollection.push({ answerData, keData });
+      answersAndKnowledgeElementCollection.push({ answerData, keData });
 
       currentPixScore += skill.pixValue;
       if (currentPixScore >= pixScoreByCompetence) {
@@ -173,9 +173,9 @@ function _makeCompetenceEvaluation({ databaseBuilder, userId, competenceId }) {
   return assessmentId;
 }
 
-function _makeUserReachPixScoreForCompetences({ databaseBuilder, userId, answersAndKnowledgeElementsCollection }) {
+function _makeUserReachPixScoreForCompetences({ databaseBuilder, userId, answersAndKnowledgeElementCollection }) {
   const answersAndKnowledgeElementsByCompetenceId = _.groupBy(
-    answersAndKnowledgeElementsCollection,
+    answersAndKnowledgeElementCollection,
     ({ keData }) => keData.competenceId,
   );
   for (const [competenceId, answersAndKnowledgeElements] of Object.entries(answersAndKnowledgeElementsByCompetenceId)) {
diff --git a/api/src/prescription/campaign/infrastructure/repositories/knowledge-element-snapshot-repository.js b/api/src/prescription/campaign/infrastructure/repositories/knowledge-element-snapshot-repository.js
index 30a3d6ece87..f8abb02be7c 100644
--- a/api/src/prescription/campaign/infrastructure/repositories/knowledge-element-snapshot-repository.js
+++ b/api/src/prescription/campaign/infrastructure/repositories/knowledge-element-snapshot-repository.js
@@ -5,6 +5,7 @@ import { DomainTransaction } from '../../../../shared/domain/DomainTransaction.j
 import { AlreadyExistingEntityError } from '../../../../shared/domain/errors.js';
 import { KnowledgeElement } from '../../../../shared/domain/models/KnowledgeElement.js';
 import * as knexUtils from '../../../../shared/infrastructure/utils/knex-utils.js';
+import { KnowledgeElementCollection } from '../../../shared/domain/models/KnowledgeElementCollection.js';
 import { CampaignParticipationKnowledgeElementSnapshots } from '../../../shared/domain/read-models/CampaignParticipationKnowledgeElementSnapshots.js';
 
 function _toKnowledgeElementCollection({ snapshot } = {}) {
diff --git a/api/src/shared/infrastructure/repositories/knowledge-element-repository.js b/api/src/shared/infrastructure/repositories/knowledge-element-repository.js
index 0539a1c459b..f95a2903f3d 100644
--- a/api/src/shared/infrastructure/repositories/knowledge-element-repository.js
+++ b/api/src/shared/infrastructure/repositories/knowledge-element-repository.js
@@ -1,24 +1,12 @@
 import _ from 'lodash';
 
 import { knex } from '../../../../db/knex-database-connection.js';
+import { KnowledgeElementCollection } from '../../../prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { DomainTransaction } from '../../domain/DomainTransaction.js';
 import { KnowledgeElement } from '../../domain/models/KnowledgeElement.js';
 
 const tableName = 'knowledge-elements';
 
-function _getUniqMostRecents(knowledgeElements) {
-  return _(knowledgeElements).orderBy('createdAt', 'desc').uniqBy('skillId').value();
-}
-
-function _dropResetKnowledgeElements(knowledgeElements) {
-  return _.reject(knowledgeElements, { status: KnowledgeElement.StatusType.RESET });
-}
-
-function _applyFilters(knowledgeElements) {
-  const uniqsMostRecentPerSkill = _getUniqMostRecents(knowledgeElements);
-  return _dropResetKnowledgeElements(uniqsMostRecentPerSkill);
-}
-
 function _findByUserIdAndLimitDateQuery({ userId, limitDate, skillIds = [] }) {
   const knexConn = DomainTransaction.getConnection();
   return knexConn(tableName).where((qb) => {
@@ -35,11 +23,10 @@ function _findByUserIdAndLimitDateQuery({ userId, limitDate, skillIds = [] }) {
 async function findAssessedByUserIdAndLimitDateQuery({ userId, limitDate, skillIds }) {
   const knowledgeElementRows = await _findByUserIdAndLimitDateQuery({ userId, limitDate, skillIds });
 
-  const knowledgeElements = _.map(
-    knowledgeElementRows,
-    (knowledgeElementRow) => new KnowledgeElement(knowledgeElementRow),
+  const keCollection = new KnowledgeElementCollection(
+    knowledgeElementRows.map((knowledgeElementRow) => new KnowledgeElement(knowledgeElementRow)),
   );
-  return _applyFilters(knowledgeElements);
+  return keCollection.latestUniqNonResetKnowledgeElements;
 }
 
 const findUniqByUserIds = function (userIds) {
@@ -69,11 +56,10 @@ const findUniqByUserIdAndAssessmentId = async function ({ userId, assessmentId }
   const query = _findByUserIdAndLimitDateQuery({ userId });
   const knowledgeElementRows = await query.where({ assessmentId });
 
-  const knowledgeElements = _.map(
-    knowledgeElementRows,
-    (knowledgeElementRow) => new KnowledgeElement(knowledgeElementRow),
+  const keCollection = new KnowledgeElementCollection(
+    knowledgeElementRows.map((knowledgeElementRow) => new KnowledgeElement(knowledgeElementRow)),
   );
-  return _applyFilters(knowledgeElements);
+  return keCollection.latestUniqNonResetKnowledgeElements;
 };
 
 const findUniqByUserIdAndCompetenceId = async function ({ userId, competenceId }) {
diff --git a/api/tests/prescription/campaign/acceptance/application/campaign-results-route_test.js b/api/tests/prescription/campaign/acceptance/application/campaign-results-route_test.js
index 1803c7e8d12..459b5705d72 100644
--- a/api/tests/prescription/campaign/acceptance/application/campaign-results-route_test.js
+++ b/api/tests/prescription/campaign/acceptance/application/campaign-results-route_test.js
@@ -1,3 +1,4 @@
+import { KnowledgeElementCollection } from '../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { Membership } from '../../../../../src/shared/domain/models/Membership.js';
 import {
   createServer,
@@ -577,7 +578,7 @@ describe('Acceptance | API | campaign-results-route', function () {
       databaseBuilder.factory.buildKnowledgeElementSnapshot({
         userId,
         campaignParticipationId: campaignParticipation.id,
-        snapshot: JSON.stringify([ke]),
+        snapshot: new KnowledgeElementCollection([ke]).toSnapsho(),
         snappedAt: campaignParticipation.sharedAt,
       });
 
diff --git a/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-assessment-results-to-stream_test.js b/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-assessment-results-to-stream_test.js
index 4073cfb34a9..48fb5e723e4 100644
--- a/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-assessment-results-to-stream_test.js
+++ b/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-assessment-results-to-stream_test.js
@@ -6,6 +6,7 @@ import dayjs from 'dayjs';
 
 import { usecases } from '../../../../../../src/prescription/campaign/domain/usecases/index.js';
 import { CampaignExternalIdTypes } from '../../../../../../src/prescription/shared/domain/constants.js';
+import { KnowledgeElementCollection } from '../../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { CAMPAIGN_FEATURES, ORGANIZATION_FEATURE } from '../../../../../../src/shared/domain/constants.js';
 import { Assessment } from '../../../../../../src/shared/domain/models/Assessment.js';
 import { CampaignParticipationStatuses, KnowledgeElement } from '../../../../../../src/shared/domain/models/index.js';
@@ -108,7 +109,7 @@ describe('Integration | Domain | Use Cases | start-writing-campaign-assessment-r
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: participant.id,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1]),
+          snapshot: new KnowledgeElementCollection([ke1]).toSnapshot(),
         });
 
         ['recSkillWeb1'].forEach((skillId) => {
@@ -201,7 +202,7 @@ describe('Integration | Domain | Use Cases | start-writing-campaign-assessment-r
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: participant.id,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1, ke2, ke3]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2, ke3]).toSnapshot(),
         });
 
         ['recSkillWeb1', 'recSkillWeb2', 'recSkillWeb3'].forEach((skillId) => {
@@ -340,7 +341,7 @@ describe('Integration | Domain | Use Cases | start-writing-campaign-assessment-r
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: participant.id,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1, ke2, ke3]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2, ke3]).toSnapshot(),
         });
 
         ['recSkillWeb1', 'recSkillWeb2', 'recSkillWeb3'].forEach((skillId) => {
@@ -449,7 +450,7 @@ describe('Integration | Domain | Use Cases | start-writing-campaign-assessment-r
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: participant.id,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1, ke2, ke3]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2, ke3]).toSnapshot(),
         });
 
         ['recSkillWeb1', 'recSkillWeb2', 'recSkillWeb3'].forEach((skillId) => {
@@ -694,7 +695,7 @@ describe('Integration | Domain | Use Cases | start-writing-campaign-assessment-r
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: participant.id,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1, ke2, ke3]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2, ke3]).toSnapshot(),
         });
 
         ['recSkillWeb1', 'recSkillWeb2', 'recSkillWeb3'].forEach((skillId) => {
diff --git a/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-profiles-collection-results-to-stream_test.js b/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-profiles-collection-results-to-stream_test.js
index 40d956f9ec7..e90b478e52b 100644
--- a/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-profiles-collection-results-to-stream_test.js
+++ b/api/tests/prescription/campaign/integration/domain/usecases/start-writing-campaign-profiles-collection-results-to-stream_test.js
@@ -11,6 +11,7 @@ import {
   CampaignExternalIdTypes,
   CampaignParticipationStatuses,
 } from '../../../../../../src/prescription/shared/domain/constants.js';
+import { KnowledgeElementCollection } from '../../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import {
   CAMPAIGN_FEATURES,
   MAX_REACHABLE_LEVEL,
@@ -96,7 +97,7 @@ describe('Integration | Domain | Use Cases | start-writing-profiles-collection-c
       databaseBuilder.factory.buildKnowledgeElementSnapshot({
         userId: participant.id,
         snappedAt: sharedAt,
-        snapshot: JSON.stringify([ke1, ke2, ke3, ke4, ke5]),
+        snapshot: new KnowledgeElementCollection([ke1, ke2, ke3, ke4, ke5]).toSnapshot(),
       });
 
       databaseBuilder.factory.learningContent.buildFramework({
diff --git a/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-collective-result-repository_test.js b/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-collective-result-repository_test.js
index d5c937dbc73..7fa75476dbf 100644
--- a/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-collective-result-repository_test.js
+++ b/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-collective-result-repository_test.js
@@ -3,6 +3,7 @@ import _ from 'lodash';
 import { CampaignCollectiveResult } from '../../../../../../src/prescription/campaign/domain/read-models/CampaignCollectiveResult.js';
 import * as campaignCollectiveResultRepository from '../../../../../../src/prescription/campaign/infrastructure/repositories/campaign-collective-result-repository.js';
 import { CampaignParticipationStatuses } from '../../../../../../src/prescription/shared/domain/constants.js';
+import { KnowledgeElementCollection } from '../../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { databaseBuilder, domainBuilder, expect } from '../../../../../test-helper.js';
 
 const { STARTED } = CampaignParticipationStatuses;
@@ -471,7 +472,9 @@ describe('Integration | Repository | Campaign collective result repository', fun
             userId: fredId,
             campaignParticipationId: userWithCampaignParticipationFred.campaignParticipation.id,
             snappedAt: userWithCampaignParticipationFred.sharedAt,
-            snapshot: JSON.stringify(knowledgeElements.map(domainBuilder.buildKnowledgeElement)),
+            snapshot: new KnowledgeElementCollection(
+              knowledgeElements.map(domainBuilder.buildKnowledgeElement),
+            ).toSnapshot(),
           });
 
           return databaseBuilder.commit();
@@ -887,54 +890,42 @@ describe('Integration | Repository | Campaign collective result repository', fun
           ];
 
           const knowledgeElementsAlice = knowledgeElementsDataAlice.map(databaseBuilder.factory.buildKnowledgeElement);
-          const snapshotsAlice = _(knowledgeElementsAlice).orderBy('createdAt', 'desc').uniqBy('skillId').value();
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationAlice.userId,
             snappedAt: userWithCampaignParticipationAlice.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsAlice),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsAlice).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationAlice.campaignParticipation.id,
           });
 
           const knowledgeElementsCharlie = knowledgeElementsDataCharlie.map(
             databaseBuilder.factory.buildKnowledgeElement,
           );
-          const snapshotsCharlie = _(knowledgeElementsCharlie)
-            .filter((o) => o.createdAt <= campaignParticipationShareDate)
-            .orderBy('createdAt', 'desc')
-            .uniqBy('skillId')
-            .value();
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationCharlie.userId,
             snappedAt: userWithCampaignParticipationCharlie.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsCharlie),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsCharlie).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationCharlie.campaignParticipation.id,
           });
 
           const knowledgeElementsBob = knowledgeElementsDataBob.map(databaseBuilder.factory.buildKnowledgeElement);
-          const snapshotsBob = _(knowledgeElementsBob)
-            .filter((o) => o.createdAt <= campaignParticipationShareDate)
-            .orderBy('createdAt', 'desc')
-            .uniqBy('skillId')
-            .value();
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationBob.userId,
             snappedAt: userWithCampaignParticipationBob.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsBob),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsBob).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationBob.campaignParticipation.id,
           });
 
           knowledgeElementsDataDan.map(databaseBuilder.factory.buildKnowledgeElement);
 
           const knowledgeElementsElo = knowledgeElementsDataElo.map(databaseBuilder.factory.buildKnowledgeElement);
-          const snapshotsElo = _(knowledgeElementsElo).orderBy('createdAt', 'desc').uniqBy('skillId').value();
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationElo.userId,
             snappedAt: userWithCampaignParticipationElo.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsElo),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsElo).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationElo.campaignParticipation.id,
           });
 
@@ -988,7 +979,7 @@ describe('Integration | Repository | Campaign collective result repository', fun
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userId,
             snappedAt: campaignParticipation.sharedAt,
-            snapshot: JSON.stringify([knowledgeElement]),
+            snapshot: new KnowledgeElementCollection([knowledgeElement]).toSnapshot(),
             campaignParticipationId: campaignParticipation.id,
           });
 
@@ -1071,26 +1062,20 @@ describe('Integration | Repository | Campaign collective result repository', fun
           ];
 
           const knowledgeElementsAlice = knowledgeElementsDataAlice.map(databaseBuilder.factory.buildKnowledgeElement);
-          const snapshotsAlice = _(knowledgeElementsAlice).orderBy('createdAt', 'desc').uniqBy('skillId').value();
 
           const knowledgeElementsBob = knowledgeElementsDataBob.map(databaseBuilder.factory.buildKnowledgeElement);
-          const snapshotsBob = _(knowledgeElementsBob)
-            .filter((o) => o.createdAt <= campaignParticipationShareDate)
-            .orderBy('createdAt', 'desc')
-            .uniqBy('skillId')
-            .value();
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationAlice.userId,
             snappedAt: userWithCampaignParticipationAlice.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsAlice),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsAlice).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationAlice.campaignParticipation.id,
           });
 
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userWithCampaignParticipationBob.userId,
             snappedAt: userWithCampaignParticipationBob.campaignParticipation.sharedAt,
-            snapshot: JSON.stringify(snapshotsBob),
+            snapshot: new KnowledgeElementCollection(knowledgeElementsBob).toSnapshot(),
             campaignParticipationId: userWithCampaignParticipationBob.campaignParticipation.id,
           });
 
diff --git a/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-profiles-collection-participation-summary-repository_test.js b/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-profiles-collection-participation-summary-repository_test.js
index 0d39edf8dd5..2f49b283237 100644
--- a/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-profiles-collection-participation-summary-repository_test.js
+++ b/api/tests/prescription/campaign/integration/infrastructure/repositories/campaign-profiles-collection-participation-summary-repository_test.js
@@ -4,6 +4,7 @@ import {
   CampaignParticipationStatuses,
   CampaignTypes,
 } from '../../../../../../src/prescription/shared/domain/constants.js';
+import { KnowledgeElementCollection } from '../../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { databaseBuilder, expect } from '../../../../../test-helper.js';
 
 const { STARTED, TO_SHARE, SHARED } = CampaignParticipationStatuses;
@@ -171,7 +172,7 @@ describe('Integration | Repository | Campaign Profiles Collection Participation
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: campaignParticipation.userId,
           snappedAt: campaignParticipation.sharedAt,
-          snapshot: JSON.stringify([ke1, ke2]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2]).toSnapshot(),
         });
 
         await databaseBuilder.commit();
diff --git a/api/tests/prescription/campaign/integration/infrastructure/repositories/knowledge-element-snapshot-repository_test.js b/api/tests/prescription/campaign/integration/infrastructure/repositories/knowledge-element-snapshot-repository_test.js
index c807408fad4..51a7acfffc2 100644
--- a/api/tests/prescription/campaign/integration/infrastructure/repositories/knowledge-element-snapshot-repository_test.js
+++ b/api/tests/prescription/campaign/integration/infrastructure/repositories/knowledge-element-snapshot-repository_test.js
@@ -138,6 +138,7 @@ describe('Integration | Repository | KnowledgeElementSnapshotRepository', functi
       databaseBuilder.factory.buildKnowledgeElementSnapshot({
         userId: userId1,
         snappedAt: snappedAt1,
+        // snapshot: new KnowledgeElementCollection([knowledgeElement1]).toSnapshot(),
         snapshot: JSON.stringify([knowledgeElement1]),
         campaignParticipationId,
       });
@@ -146,6 +147,7 @@ describe('Integration | Repository | KnowledgeElementSnapshotRepository', functi
       databaseBuilder.factory.buildKnowledgeElementSnapshot({
         userId: userId2,
         snappedAt: snappedAt2,
+        // snapshot: new KnowledgeElementCollection([knowledgeElement2]).toSnapshot(),
         snapshot: JSON.stringify([knowledgeElement2]),
         campaignParticipationId,
       });
diff --git a/api/tests/shared/integration/domain/services/placement-profile-service_test.js b/api/tests/shared/integration/domain/services/placement-profile-service_test.js
index be91747e377..d46490a9353 100644
--- a/api/tests/shared/integration/domain/services/placement-profile-service_test.js
+++ b/api/tests/shared/integration/domain/services/placement-profile-service_test.js
@@ -1,3 +1,4 @@
+import { KnowledgeElementCollection } from '../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { LOCALE } from '../../../../../src/shared/domain/constants.js';
 import {
   CampaignParticipationStatuses,
@@ -529,7 +530,7 @@ describe('Shared | Integration | Domain | Services | Placement Profile Service',
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: userId,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke]),
+          snapshot: new KnowledgeElementCollection([ke]).toSnapsho(),
         });
 
         await databaseBuilder.commit();
@@ -579,7 +580,7 @@ describe('Shared | Integration | Domain | Services | Placement Profile Service',
         databaseBuilder.factory.buildKnowledgeElementSnapshot({
           userId: userId,
           snappedAt: sharedAt,
-          snapshot: JSON.stringify([ke1, ke2]),
+          snapshot: new KnowledgeElementCollection([ke1, ke2]).toSnapshot(),
         });
         await databaseBuilder.commit();
 
@@ -607,7 +608,7 @@ describe('Shared | Integration | Domain | Services | Placement Profile Service',
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userId,
             snappedAt: sharedAt,
-            snapshot: JSON.stringify([ke]),
+            snapshot: new KnowledgeElementCollection([ke]).toSnapsho(),
           });
 
           await databaseBuilder.commit();
@@ -642,7 +643,7 @@ describe('Shared | Integration | Domain | Services | Placement Profile Service',
           databaseBuilder.factory.buildKnowledgeElementSnapshot({
             userId: userId,
             snappedAt: sharedAt,
-            snapshot: JSON.stringify([ke]),
+            snapshot: new KnowledgeElementCollection([ke]).toSnapsho(),
           });
 
           await databaseBuilder.commit();
diff --git a/api/tests/shared/integration/infrastructure/repositories/knowledge-element-repository_test.js b/api/tests/shared/integration/infrastructure/repositories/knowledge-element-repository_test.js
index 706f9a5d6c2..aa3199b7d44 100644
--- a/api/tests/shared/integration/infrastructure/repositories/knowledge-element-repository_test.js
+++ b/api/tests/shared/integration/infrastructure/repositories/knowledge-element-repository_test.js
@@ -1,5 +1,6 @@
 import _ from 'lodash';
 
+import { KnowledgeElementCollection } from '../../../../../src/prescription/shared/domain/models/KnowledgeElementCollection.js';
 import { DomainTransaction } from '../../../../../src/shared/domain/DomainTransaction.js';
 import { KnowledgeElement } from '../../../../../src/shared/domain/models/KnowledgeElement.js';
 import * as knowledgeElementRepository from '../../../../../src/shared/infrastructure/repositories/knowledge-element-repository.js';