diff --git a/packages/datastore/src/types.ts b/packages/datastore/src/types.ts
index bc9b34b2..02fd04e9 100644
--- a/packages/datastore/src/types.ts
+++ b/packages/datastore/src/types.ts
@@ -10,7 +10,6 @@
 export interface BaseDocument {
   id: string;
   productId: string;
-  [key: string]: unknown;
 }
 
 // ── Filter operators ────────────────────────────────────────────────────────
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 248a9cb8..80ea7a16 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -558,6 +558,9 @@ importers:
       '@bytelyst/cosmos':
         specifier: workspace:*
         version: link:../../packages/cosmos
+      '@bytelyst/datastore':
+        specifier: workspace:*
+        version: link:../../packages/datastore
       '@bytelyst/errors':
         specifier: workspace:*
         version: link:../../packages/errors
diff --git a/services/platform-service/package.json b/services/platform-service/package.json
index e5d287cd..b1175c80 100644
--- a/services/platform-service/package.json
+++ b/services/platform-service/package.json
@@ -19,6 +19,7 @@
     "@bytelyst/blob": "workspace:*",
     "@bytelyst/config": "workspace:*",
     "@bytelyst/cosmos": "workspace:*",
+    "@bytelyst/datastore": "workspace:*",
     "@bytelyst/errors": "workspace:*",
     "@bytelyst/events": "workspace:*",
     "@bytelyst/fastify-core": "workspace:*",
diff --git a/services/platform-service/src/lib/datastore.ts b/services/platform-service/src/lib/datastore.ts
new file mode 100644
index 00000000..0e7cf5c4
--- /dev/null
+++ b/services/platform-service/src/lib/datastore.ts
@@ -0,0 +1,67 @@
+/**
+ * Cloud-agnostic datastore bridge for platform-service.
+ *
+ * Wraps @bytelyst/datastore with platform-service container registry config.
+ * Repositories import getCollection() from here instead of getContainer() from cosmos.
+ *
+ * Migration: Replace `import { getContainer } from '../../lib/cosmos.js'`
+ *       with `import { getCollection } from '../../lib/datastore.js'`
+ */
+
+import {
+  type DatastoreProvider,
+  type DocumentCollection,
+  type BaseDocument,
+  setDatastore,
+  CosmosDatastoreProvider,
+  MemoryDatastoreProvider,
+} from '@bytelyst/datastore';
+
+let _provider: DatastoreProvider | null = null;
+
+/**
+ * Initialize the datastore provider.
+ * Call once at service startup (before any repository calls).
+ */
+export function initDatastore(): DatastoreProvider {
+  if (_provider) return _provider;
+
+  const dbProvider = (process.env.DB_PROVIDER || 'cosmos').toLowerCase();
+
+  if (dbProvider === 'memory') {
+    _provider = new MemoryDatastoreProvider();
+  } else {
+    _provider = new CosmosDatastoreProvider();
+  }
+
+  setDatastore(_provider);
+  return _provider;
+}
+
+/**
+ * Inject a provider directly (for testing).
+ */
+export function setProvider(provider: DatastoreProvider): void {
+  _provider = provider;
+}
+
+/**
+ * Get a typed collection from the datastore.
+ * Drop-in replacement for getContainer() — returns a DocumentCollection instead of a Cosmos Container.
+ */
+export function getCollection<T extends BaseDocument = BaseDocument>(
+  name: string,
+  partitionKeyPath: string = '/productId'
+): DocumentCollection<T> {
+  if (!_provider) {
+    initDatastore();
+  }
+  return _provider!.getCollection<T>(name, partitionKeyPath);
+}
+
+/**
+ * @internal — for testing only
+ */
+export function _resetDatastoreProvider(): void {
+  _provider = null;
+}
diff --git a/services/platform-service/src/modules/comments/repository.ts b/services/platform-service/src/modules/comments/repository.ts
index 8650c3a6..1e7f5f2d 100644
--- a/services/platform-service/src/modules/comments/repository.ts
+++ b/services/platform-service/src/modules/comments/repository.ts
@@ -1,45 +1,36 @@
 /**
- * Comments repository — Cosmos DB CRUD.
+ * Comments repository — cloud-agnostic via @bytelyst/datastore.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { CommentDoc } from './types.js';
 
-function container() {
-  return getContainer('tracker_comments');
+function collection() {
+  return getCollection<CommentDoc>('tracker_comments', '/id');
 }
 
 export async function listByItem(itemId: string): Promise<CommentDoc[]> {
-  const { resources } = await container()
-    .items.query<CommentDoc>({
-      query: 'SELECT * FROM c WHERE c.itemId = @itemId ORDER BY c.createdAt ASC',
-      parameters: [{ name: '@itemId', value: itemId }],
-    })
-    .fetchAll();
-  return resources;
+  return collection().findMany({
+    filter: { itemId },
+    sort: { createdAt: 1 },
+  });
 }
 
 export async function getById(id: string): Promise<CommentDoc | null> {
   try {
-    const { resource } = await container().item(id, id).read<CommentDoc>();
-    return resource ?? null;
+    return await collection().findById(id, id);
   } catch {
     return null;
   }
 }
 
 export async function create(doc: CommentDoc): Promise<CommentDoc> {
-  const { resource } = await container().items.create(doc);
-  return resource as CommentDoc;
+  return collection().create(doc);
 }
 
 export async function update(id: string, updates: Partial<CommentDoc>): Promise<CommentDoc | null> {
   try {
-    const { resource: existing } = await container().item(id, id).read<CommentDoc>();
-    if (!existing) return null;
-    const merged = { ...existing, ...updates, updatedAt: new Date().toISOString() };
-    const { resource } = await container().item(id, id).replace(merged);
-    return resource as CommentDoc;
+    return await collection().update(id, id, { ...updates, updatedAt: new Date().toISOString() });
   } catch {
     return null;
   }
@@ -47,7 +38,7 @@ export async function update(id: string, updates: Partial<CommentDoc>): Promise<
 
 export async function remove(id: string): Promise<boolean> {
   try {
-    await container().item(id, id).delete();
+    await collection().delete(id, id);
     return true;
   } catch {
     return false;
@@ -55,11 +46,5 @@ export async function remove(id: string): Promise<boolean> {
 }
 
 export async function countByItem(itemId: string): Promise<number> {
-  const { resources } = await container()
-    .items.query<number>({
-      query: 'SELECT VALUE COUNT(1) FROM c WHERE c.itemId = @itemId',
-      parameters: [{ name: '@itemId', value: itemId }],
-    })
-    .fetchAll();
-  return resources[0] ?? 0;
+  return collection().count({ itemId });
 }
diff --git a/services/platform-service/src/modules/flags/repository.ts b/services/platform-service/src/modules/flags/repository.ts
index 2bfb0347..c42d60a6 100644
--- a/services/platform-service/src/modules/flags/repository.ts
+++ b/services/platform-service/src/modules/flags/repository.ts
@@ -1,40 +1,29 @@
 /**
- * Feature flags repository — Cosmos DB CRUD.
+ * Feature flags repository — cloud-agnostic via @bytelyst/datastore.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { FeatureFlagDoc } from './types.js';
 
-function container() {
-  return getContainer('feature_flags');
+function collection() {
+  return getCollection<FeatureFlagDoc>('feature_flags', '/productId');
 }
 
 export async function list(productId: string): Promise<FeatureFlagDoc[]> {
-  const { resources } = await container()
-    .items.query<FeatureFlagDoc>({
-      query: 'SELECT * FROM c WHERE c.productId = @productId ORDER BY c.key ASC',
-      parameters: [{ name: '@productId', value: productId }],
-    })
-    .fetchAll();
-  return resources;
+  return collection().findMany({
+    filter: { productId },
+    sort: { key: 1 },
+  });
 }
 
 export async function getByKey(key: string, productId: string): Promise<FeatureFlagDoc | null> {
-  const { resources } = await container()
-    .items.query<FeatureFlagDoc>({
-      query: 'SELECT * FROM c WHERE c.productId = @productId AND c.key = @key',
-      parameters: [
-        { name: '@productId', value: productId },
-        { name: '@key', value: key },
-      ],
-    })
-    .fetchAll();
-  return resources[0] ?? null;
+  return collection().findOne({
+    filter: { productId, key },
+  });
 }
 
 export async function create(doc: FeatureFlagDoc): Promise<FeatureFlagDoc> {
-  const { resource } = await container().items.create(doc);
-  return resource as FeatureFlagDoc;
+  return collection().create(doc);
 }
 
 export async function update(
@@ -42,11 +31,7 @@ export async function update(
   updates: Partial<FeatureFlagDoc>
 ): Promise<FeatureFlagDoc | null> {
   try {
-    const { resource: existing } = await container().item(id, id).read<FeatureFlagDoc>();
-    if (!existing) return null;
-    const merged = { ...existing, ...updates, updatedAt: new Date().toISOString() };
-    const { resource } = await container().item(id, id).replace(merged);
-    return resource as FeatureFlagDoc;
+    return await collection().update(id, id, { ...updates, updatedAt: new Date().toISOString() });
   } catch {
     return null;
   }
@@ -54,7 +39,7 @@ export async function update(
 
 export async function remove(id: string): Promise<boolean> {
   try {
-    await container().item(id, id).delete();
+    await collection().delete(id, id);
     return true;
   } catch {
     return false;
diff --git a/services/platform-service/src/modules/products/repository.test.ts b/services/platform-service/src/modules/products/repository.test.ts
index 1c632e67..f1387d20 100644
--- a/services/platform-service/src/modules/products/repository.test.ts
+++ b/services/platform-service/src/modules/products/repository.test.ts
@@ -1,24 +1,10 @@
 /**
- * Repository tests for products module — mocked Cosmos DB.
+ * Repository tests for products module — in-memory datastore.
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest';
-
-const mockFetchAll = vi.fn();
-const mockCreate = vi.fn();
-const mockRead = vi.fn();
-const mockReplace = vi.fn();
-
-vi.mock('../../lib/cosmos.js', () => ({
-  getContainer: vi.fn(() => ({
-    items: {
-      query: () => ({ fetchAll: mockFetchAll }),
-      create: mockCreate,
-    },
-    item: () => ({ read: mockRead, replace: mockReplace }),
-  })),
-}));
-
+import { describe, it, expect, beforeEach, afterAll } from 'vitest';
+import { MemoryDatastoreProvider } from '@bytelyst/datastore';
+import { setProvider, _resetDatastoreProvider } from '../../lib/datastore.js';
 import { getAll, getById, create, update } from './repository.js';
 import type { ProductDoc } from './types.js';
 
@@ -37,20 +23,27 @@ const baseProduct: ProductDoc = {
   updatedAt: '2026-02-16T00:00:00Z',
 };
 
+let memProvider: MemoryDatastoreProvider;
+
 describe('products repository', () => {
   beforeEach(() => {
-    vi.clearAllMocks();
+    memProvider = new MemoryDatastoreProvider();
+    setProvider(memProvider);
+  });
+
+  afterAll(() => {
+    _resetDatastoreProvider();
   });
 
   describe('getAll', () => {
     it('returns all products', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [baseProduct] });
+      await create(baseProduct);
       const result = await getAll();
-      expect(result).toEqual([baseProduct]);
+      expect(result).toHaveLength(1);
+      expect(result[0]!.id).toBe('lysnrai');
     });
 
     it('returns empty array when no products', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [] });
       const result = await getAll();
       expect(result).toEqual([]);
     });
@@ -58,27 +51,19 @@ describe('products repository', () => {
 
   describe('getById', () => {
     it('returns product when found', async () => {
-      mockRead.mockResolvedValue({ resource: baseProduct });
+      await create(baseProduct);
       const result = await getById('lysnrai');
       expect(result).toEqual(baseProduct);
     });
 
     it('returns null when not found', async () => {
-      mockRead.mockRejectedValue(new Error('Not found'));
       const result = await getById('nonexistent');
       expect(result).toBeNull();
     });
-
-    it('returns null when resource is undefined', async () => {
-      mockRead.mockResolvedValue({ resource: undefined });
-      const result = await getById('lysnrai');
-      expect(result).toBeNull();
-    });
   });
 
   describe('create', () => {
     it('creates and returns product', async () => {
-      mockCreate.mockResolvedValue({ resource: baseProduct });
       const result = await create(baseProduct);
       expect(result).toEqual(baseProduct);
     });
@@ -86,21 +71,14 @@ describe('products repository', () => {
 
   describe('update', () => {
     it('merges updates and returns product', async () => {
-      mockRead.mockResolvedValue({ resource: baseProduct });
-      const updated = { ...baseProduct, displayName: 'LysnrAI Pro' };
-      mockReplace.mockResolvedValue({ resource: updated });
+      await create(baseProduct);
       const result = await update('lysnrai', { displayName: 'LysnrAI Pro' });
-      expect(result).toEqual(updated);
+      expect(result).not.toBeNull();
+      expect(result!.displayName).toBe('LysnrAI Pro');
+      expect(result!.id).toBe('lysnrai');
     });
 
     it('returns null when not found', async () => {
-      mockRead.mockResolvedValue({ resource: undefined });
-      const result = await update('nonexistent', { displayName: 'Test' });
-      expect(result).toBeNull();
-    });
-
-    it('returns null on error', async () => {
-      mockRead.mockRejectedValue(new Error('Not found'));
       const result = await update('nonexistent', { displayName: 'Test' });
       expect(result).toBeNull();
     });
diff --git a/services/platform-service/src/modules/products/repository.ts b/services/platform-service/src/modules/products/repository.ts
index 9f8f12e2..b95b2897 100644
--- a/services/platform-service/src/modules/products/repository.ts
+++ b/services/platform-service/src/modules/products/repository.ts
@@ -1,36 +1,31 @@
 /**
- * Products repository — Cosmos DB CRUD.
+ * Products repository — cloud-agnostic via @bytelyst/datastore.
  * Products are the central registry; productId is the partition key.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { ProductDoc } from './types.js';
 
-function container() {
-  return getContainer('products');
+function collection() {
+  return getCollection<ProductDoc>('products', '/productId');
 }
 
 export async function getAll(): Promise<ProductDoc[]> {
-  const { resources } = await container()
-    .items.query<ProductDoc>({
-      query: 'SELECT * FROM c ORDER BY c.displayName ASC',
-    })
-    .fetchAll();
-  return resources;
+  return collection().findMany({
+    sort: { displayName: 1 },
+  });
 }
 
 export async function getById(productId: string): Promise<ProductDoc | null> {
   try {
-    const { resource } = await container().item(productId, productId).read<ProductDoc>();
-    return resource ?? null;
+    return await collection().findById(productId, productId);
   } catch {
     return null;
   }
 }
 
 export async function create(doc: ProductDoc): Promise<ProductDoc> {
-  const { resource } = await container().items.create(doc);
-  return resource as ProductDoc;
+  return collection().create(doc);
 }
 
 export async function update(
@@ -38,11 +33,10 @@ export async function update(
   updates: Partial<ProductDoc>
 ): Promise<ProductDoc | null> {
   try {
-    const { resource: existing } = await container().item(productId, productId).read<ProductDoc>();
-    if (!existing) return null;
-    const merged = { ...existing, ...updates, updatedAt: new Date().toISOString() };
-    const { resource } = await container().item(productId, productId).replace(merged);
-    return resource as ProductDoc;
+    return await collection().update(productId, productId, {
+      ...updates,
+      updatedAt: new Date().toISOString(),
+    });
   } catch {
     return null;
   }
diff --git a/services/platform-service/src/modules/settings/repository.test.ts b/services/platform-service/src/modules/settings/repository.test.ts
index 54295120..635e5aee 100644
--- a/services/platform-service/src/modules/settings/repository.test.ts
+++ b/services/platform-service/src/modules/settings/repository.test.ts
@@ -1,19 +1,10 @@
 /**
- * Repository tests for settings module — mocked Cosmos DB.
+ * Repository tests for settings module — in-memory datastore.
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest';
-
-const mockRead = vi.fn();
-const mockUpsert = vi.fn();
-
-vi.mock('../../lib/cosmos.js', () => ({
-  getContainer: vi.fn(() => ({
-    items: { upsert: mockUpsert },
-    item: () => ({ read: mockRead }),
-  })),
-}));
-
+import { describe, it, expect, beforeEach, afterAll } from 'vitest';
+import { MemoryDatastoreProvider } from '@bytelyst/datastore';
+import { setProvider, _resetDatastoreProvider } from '../../lib/datastore.js';
 import { getSettingsId, getByUserId, upsert } from './repository.js';
 import type { UserSettingsDoc } from './types.js';
 
@@ -29,7 +20,11 @@ const baseSettings: UserSettingsDoc = {
 
 describe('settings repository', () => {
   beforeEach(() => {
-    vi.clearAllMocks();
+    setProvider(new MemoryDatastoreProvider());
+  });
+
+  afterAll(() => {
+    _resetDatastoreProvider();
   });
 
   describe('getSettingsId', () => {
@@ -44,19 +39,12 @@ describe('settings repository', () => {
 
   describe('getByUserId', () => {
     it('returns settings when found', async () => {
-      mockRead.mockResolvedValue({ resource: baseSettings });
+      await upsert(baseSettings);
       const result = await getByUserId('user_1', 'lysnrai');
       expect(result).toEqual(baseSettings);
     });
 
     it('returns null when not found', async () => {
-      mockRead.mockRejectedValue(new Error('Not found'));
-      const result = await getByUserId('user_1', 'lysnrai');
-      expect(result).toBeNull();
-    });
-
-    it('returns null when resource is undefined', async () => {
-      mockRead.mockResolvedValue({ resource: undefined });
       const result = await getByUserId('user_1', 'lysnrai');
       expect(result).toBeNull();
     });
@@ -64,7 +52,6 @@ describe('settings repository', () => {
 
   describe('upsert', () => {
     it('upserts and returns settings', async () => {
-      mockUpsert.mockResolvedValue({ resource: baseSettings });
       const result = await upsert(baseSettings);
       expect(result).toEqual(baseSettings);
     });
diff --git a/services/platform-service/src/modules/settings/repository.ts b/services/platform-service/src/modules/settings/repository.ts
index ea7ba268..8df06de3 100644
--- a/services/platform-service/src/modules/settings/repository.ts
+++ b/services/platform-service/src/modules/settings/repository.ts
@@ -1,12 +1,12 @@
 /**
- * User settings repository — Cosmos DB CRUD for settings + device overrides.
+ * User settings repository — cloud-agnostic via @bytelyst/datastore.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { UserSettingsDoc } from './types.js';
 
-function container() {
-  return getContainer('settings');
+function collection() {
+  return getCollection<UserSettingsDoc>('settings', '/userId');
 }
 
 export function getSettingsId(productId: string, userId: string): string {
@@ -19,14 +19,12 @@ export async function getByUserId(
 ): Promise<UserSettingsDoc | null> {
   const id = getSettingsId(productId, userId);
   try {
-    const { resource } = await container().item(id, userId).read<UserSettingsDoc>();
-    return resource ?? null;
+    return await collection().findById(id, userId);
   } catch {
     return null;
   }
 }
 
 export async function upsert(doc: UserSettingsDoc): Promise<UserSettingsDoc> {
-  const { resource } = await container().items.upsert<UserSettingsDoc>(doc);
-  return resource!;
+  return collection().upsert(doc);
 }
diff --git a/services/platform-service/src/modules/themes/repository.ts b/services/platform-service/src/modules/themes/repository.ts
index 0e65e552..8f392993 100644
--- a/services/platform-service/src/modules/themes/repository.ts
+++ b/services/platform-service/src/modules/themes/repository.ts
@@ -1,65 +1,53 @@
 /**
- * Theme repository — Cosmos DB.
+ * Theme repository — cloud-agnostic via @bytelyst/datastore.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { ThemeDoc } from './types.js';
 
-function container() {
-  return getContainer('themes');
+function collection() {
+  return getCollection<ThemeDoc>('themes', '/id');
 }
 
 export async function getAll(productId: string): Promise<ThemeDoc[]> {
-  const { resources } = await container()
-    .items.query<ThemeDoc>({
-      query:
-        "SELECT * FROM c WHERE c.productId = @productId AND c.type = 'theme' ORDER BY c.created_at DESC",
-      parameters: [{ name: '@productId', value: productId }],
-    })
-    .fetchAll();
-  return resources;
+  return collection().findMany({
+    filter: { productId, type: 'theme' },
+    sort: { created_at: -1 },
+  });
 }
 
 export async function getById(id: string): Promise<ThemeDoc | null> {
   try {
-    const { resource } = await container().item(id, id).read<ThemeDoc>();
-    return resource ?? null;
+    return await collection().findById(id, id);
   } catch {
     return null;
   }
 }
 
 export async function getActive(productId: string): Promise<ThemeDoc | null> {
-  const { resources } = await container()
-    .items.query<ThemeDoc>({
-      query:
-        "SELECT * FROM c WHERE c.productId = @productId AND c.type = 'theme' AND c.is_active = true ORDER BY c.is_default DESC, c.created_at DESC OFFSET 0 LIMIT 1",
-      parameters: [{ name: '@productId', value: productId }],
-    })
-    .fetchAll();
-  return resources[0] ?? null;
+  return collection().findOne({
+    filter: { productId, type: 'theme', is_active: true },
+    sort: { is_default: -1, created_at: -1 },
+    limit: 1,
+  });
 }
 
 export async function create(theme: ThemeDoc): Promise<ThemeDoc> {
-  const { resource } = await container().items.create(theme);
-  return resource as ThemeDoc;
+  return collection().create(theme);
 }
 
 export async function update(
   id: string,
   updates: Record<string, unknown>
 ): Promise<ThemeDoc | null> {
-  const existing = await getById(id);
-  if (!existing) return null;
-
-  const merged = {
-    ...existing,
-    ...updates,
-    updated_at: new Date().toISOString(),
-  };
-
-  const { resource } = await container().item(id, id).replace(merged);
-  return resource as ThemeDoc;
+  try {
+    return await collection().update(id, id, {
+      ...updates,
+      updated_at: new Date().toISOString(),
+    } as Partial<ThemeDoc>);
+  } catch {
+    return null;
+  }
 }
 
 export async function setActive(id: string, productId: string): Promise<boolean> {
@@ -67,25 +55,15 @@ export async function setActive(id: string, productId: string): Promise<boolean>
   if (!theme) return false;
 
   // Deactivate all others for this product
-  const { resources: activeThemes } = await container()
-    .items.query<ThemeDoc>({
-      query:
-        "SELECT * FROM c WHERE c.productId = @productId AND c.type = 'theme' AND c.is_active = true AND c.id != @excludeId",
-      parameters: [
-        { name: '@productId', value: productId },
-        { name: '@excludeId', value: id },
-      ],
-    })
-    .fetchAll();
+  const activeThemes = await collection().findMany({
+    filter: { productId, type: 'theme', is_active: true, id: { $ne: id } },
+  });
 
   for (const item of activeThemes) {
-    await container()
-      .item(item.id, item.id)
-      .replace({
-        ...item,
-        is_active: false,
-        updated_at: new Date().toISOString(),
-      });
+    await collection().update(item.id, item.id, {
+      is_active: false,
+      updated_at: new Date().toISOString(),
+    } as Partial<ThemeDoc>);
   }
 
   // Activate the target theme
@@ -95,7 +73,7 @@ export async function setActive(id: string, productId: string): Promise<boolean>
 
 export async function remove(id: string): Promise<boolean> {
   try {
-    await container().item(id, id).delete();
+    await collection().delete(id, id);
     return true;
   } catch {
     return false;
diff --git a/services/platform-service/src/modules/votes/repository.test.ts b/services/platform-service/src/modules/votes/repository.test.ts
index fb351d73..9ae24253 100644
--- a/services/platform-service/src/modules/votes/repository.test.ts
+++ b/services/platform-service/src/modules/votes/repository.test.ts
@@ -1,23 +1,10 @@
 /**
- * Repository tests for votes module — mocked Cosmos DB.
+ * Repository tests for votes module — in-memory datastore.
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest';
-
-const mockFetchAll = vi.fn();
-const mockCreate = vi.fn();
-const mockDelete = vi.fn();
-
-vi.mock('../../lib/cosmos.js', () => ({
-  getContainer: vi.fn(() => ({
-    items: {
-      query: () => ({ fetchAll: mockFetchAll }),
-      create: mockCreate,
-    },
-    item: () => ({ delete: mockDelete }),
-  })),
-}));
-
+import { describe, it, expect, beforeEach, afterAll } from 'vitest';
+import { MemoryDatastoreProvider } from '@bytelyst/datastore';
+import { setProvider, _resetDatastoreProvider } from '../../lib/datastore.js';
 import { getByItemAndUser, countByItem, listByItem, create, remove } from './repository.js';
 import type { VoteDoc } from './types.js';
 
@@ -31,18 +18,21 @@ const baseVote: VoteDoc = {
 
 describe('votes repository', () => {
   beforeEach(() => {
-    vi.clearAllMocks();
+    setProvider(new MemoryDatastoreProvider());
+  });
+
+  afterAll(() => {
+    _resetDatastoreProvider();
   });
 
   describe('getByItemAndUser', () => {
     it('returns vote when found', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [baseVote] });
+      await create(baseVote);
       const result = await getByItemAndUser('item_1', 'user_1');
       expect(result).toEqual(baseVote);
     });
 
     it('returns null when not found', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [] });
       const result = await getByItemAndUser('item_1', 'user_1');
       expect(result).toBeNull();
     });
@@ -50,13 +40,13 @@ describe('votes repository', () => {
 
   describe('countByItem', () => {
     it('returns count', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [5] });
+      await create(baseVote);
+      await create({ ...baseVote, id: 'vote_2', userId: 'user_2' });
       const result = await countByItem('item_1');
-      expect(result).toBe(5);
+      expect(result).toBe(2);
     });
 
     it('returns 0 when no votes', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [] });
       const result = await countByItem('item_1');
       expect(result).toBe(0);
     });
@@ -64,13 +54,13 @@ describe('votes repository', () => {
 
   describe('listByItem', () => {
     it('returns votes for item', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [baseVote] });
+      await create(baseVote);
       const result = await listByItem('item_1');
-      expect(result).toEqual([baseVote]);
+      expect(result).toHaveLength(1);
+      expect(result[0]!.id).toBe('vote_1');
     });
 
     it('returns empty array when no votes', async () => {
-      mockFetchAll.mockResolvedValue({ resources: [] });
       const result = await listByItem('item_1');
       expect(result).toEqual([]);
     });
@@ -78,7 +68,6 @@ describe('votes repository', () => {
 
   describe('create', () => {
     it('creates and returns vote', async () => {
-      mockCreate.mockResolvedValue({ resource: baseVote });
       const result = await create(baseVote);
       expect(result).toEqual(baseVote);
     });
@@ -86,15 +75,14 @@ describe('votes repository', () => {
 
   describe('remove', () => {
     it('deletes and returns true', async () => {
-      mockDelete.mockResolvedValue(undefined);
+      await create(baseVote);
       const result = await remove('vote_1');
       expect(result).toBe(true);
     });
 
-    it('returns false on error', async () => {
-      mockDelete.mockRejectedValue(new Error('Not found'));
-      const result = await remove('vote_1');
-      expect(result).toBe(false);
+    it('returns true even for nonexistent (idempotent delete)', async () => {
+      const result = await remove('nonexistent');
+      expect(result).toBe(true);
     });
   });
 });
diff --git a/services/platform-service/src/modules/votes/repository.ts b/services/platform-service/src/modules/votes/repository.ts
index bc42bc3c..f5956e9d 100644
--- a/services/platform-service/src/modules/votes/repository.ts
+++ b/services/platform-service/src/modules/votes/repository.ts
@@ -1,55 +1,38 @@
 /**
- * Votes repository — Cosmos DB CRUD.
+ * Votes repository — cloud-agnostic via @bytelyst/datastore.
  */
 
-import { getContainer } from '../../lib/cosmos.js';
+import { getCollection } from '../../lib/datastore.js';
 import type { VoteDoc } from './types.js';
 
-function container() {
-  return getContainer('tracker_votes');
+function collection() {
+  return getCollection<VoteDoc>('tracker_votes', '/id');
 }
 
 export async function getByItemAndUser(itemId: string, userId: string): Promise<VoteDoc | null> {
-  const { resources } = await container()
-    .items.query<VoteDoc>({
-      query: 'SELECT * FROM c WHERE c.itemId = @itemId AND c.userId = @userId',
-      parameters: [
-        { name: '@itemId', value: itemId },
-        { name: '@userId', value: userId },
-      ],
-    })
-    .fetchAll();
-  return resources[0] ?? null;
+  return collection().findOne({
+    filter: { itemId, userId },
+  });
 }
 
 export async function countByItem(itemId: string): Promise<number> {
-  const { resources } = await container()
-    .items.query<number>({
-      query: 'SELECT VALUE COUNT(1) FROM c WHERE c.itemId = @itemId',
-      parameters: [{ name: '@itemId', value: itemId }],
-    })
-    .fetchAll();
-  return resources[0] ?? 0;
+  return collection().count({ itemId });
 }
 
 export async function listByItem(itemId: string): Promise<VoteDoc[]> {
-  const { resources } = await container()
-    .items.query<VoteDoc>({
-      query: 'SELECT * FROM c WHERE c.itemId = @itemId ORDER BY c.createdAt DESC',
-      parameters: [{ name: '@itemId', value: itemId }],
-    })
-    .fetchAll();
-  return resources;
+  return collection().findMany({
+    filter: { itemId },
+    sort: { createdAt: -1 },
+  });
 }
 
 export async function create(doc: VoteDoc): Promise<VoteDoc> {
-  const { resource } = await container().items.create(doc);
-  return resource as VoteDoc;
+  return collection().create(doc);
 }
 
 export async function remove(id: string): Promise<boolean> {
   try {
-    await container().item(id, id).delete();
+    await collection().delete(id, id);
     return true;
   } catch {
     return false;