diff --git a/services/platform-service/src/modules/telemetry/cross-product.test.ts b/services/platform-service/src/modules/telemetry/cross-product.test.ts
new file mode 100644
index 00000000..3d48315a
--- /dev/null
+++ b/services/platform-service/src/modules/telemetry/cross-product.test.ts
@@ -0,0 +1,191 @@
+/**
+ * Cross-product telemetry tests — multi-product query endpoints.
+ */
+
+import { describe, it, expect, beforeAll } from 'vitest';
+import {
+  queryCrossProductSummary,
+  queryCrossProductDaily,
+  queryCrossProductClusters,
+} from './repository.js';
+import { getCollection } from '../../lib/datastore.js';
+import type { TelemetryEventDoc, TelemetryErrorCluster } from './types.js';
+
+function eventsCollection() {
+  return getCollection<TelemetryEventDoc>('telemetry_events', '/pk');
+}
+
+function clustersCollection() {
+  return getCollection<TelemetryErrorCluster>('telemetry_error_clusters', '/pk');
+}
+
+function makeEvent(
+  productId: string,
+  overrides: Partial<TelemetryEventDoc> = {}
+): TelemetryEventDoc {
+  const id = `evt_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`;
+  return {
+    id,
+    productId,
+    anonymousInstallId: '660e8400-e29b-41d4-a716-446655440001',
+    sessionId: 'sess_test',
+    platform: 'ios',
+    channel: 'mobile_app',
+    osFamily: 'ios',
+    appVersion: '1.0.0',
+    buildNumber: '1',
+    releaseChannel: 'prod',
+    eventType: 'info',
+    module: 'core',
+    eventName: 'app_started',
+    occurredAt: '2026-03-19T10:00:00.000Z',
+    pk: `${productId}:202603:ios`,
+    receivedAt: new Date().toISOString(),
+    ttl: 2592000,
+    ...overrides,
+  };
+}
+
+function makeCluster(
+  productId: string,
+  overrides: Partial<TelemetryErrorCluster> = {}
+): TelemetryErrorCluster {
+  const fp = Math.random().toString(36).slice(2, 10);
+  return {
+    id: `${fp}:202603`,
+    pk: `${productId}:ios:core`,
+    productId,
+    fingerprint: fp,
+    platform: 'ios',
+    channel: 'mobile_app',
+    module: 'core',
+    eventName: 'crash',
+    affectedVersions: [
+      { appVersion: '1.0.0', buildNumber: '1', count: 1, lastSeenAt: new Date().toISOString() },
+    ],
+    firstSeenAt: new Date().toISOString(),
+    lastSeenAt: new Date().toISOString(),
+    totalCount: 5,
+    affectedUserIds: [],
+    affectedInstallIds: ['inst1'],
+    affectedOsFamilies: ['ios'],
+    severity: 'error',
+    status: 'open',
+    ttl: 7776000,
+    ...overrides,
+  };
+}
+
+describe('cross-product telemetry', () => {
+  beforeAll(async () => {
+    // Seed events for two products
+    const events = [
+      makeEvent('product-a', {
+        eventType: 'info',
+        module: 'auth',
+        occurredAt: '2026-03-18T10:00:00.000Z',
+      }),
+      makeEvent('product-a', {
+        eventType: 'error',
+        module: 'auth',
+        occurredAt: '2026-03-18T11:00:00.000Z',
+      }),
+      makeEvent('product-a', {
+        eventType: 'info',
+        module: 'sync',
+        occurredAt: '2026-03-19T10:00:00.000Z',
+      }),
+      makeEvent('product-b', {
+        eventType: 'info',
+        module: 'core',
+        occurredAt: '2026-03-19T10:00:00.000Z',
+        platform: 'web' as const,
+      }),
+      makeEvent('product-b', {
+        eventType: 'fatal',
+        module: 'core',
+        occurredAt: '2026-03-19T11:00:00.000Z',
+        platform: 'web' as const,
+      }),
+    ];
+    for (const e of events) {
+      await eventsCollection().upsert(e);
+    }
+
+    // Seed clusters
+    await clustersCollection().upsert(makeCluster('product-a', { totalCount: 10 }));
+    await clustersCollection().upsert(makeCluster('product-b', { totalCount: 3 }));
+  });
+
+  it('queryCrossProductSummary returns per-product stats', async () => {
+    const results = await queryCrossProductSummary(['product-a', 'product-b']);
+
+    expect(results).toHaveLength(2);
+
+    const a = results.find(r => r.productId === 'product-a')!;
+    expect(a.totalEvents).toBeGreaterThanOrEqual(3);
+    expect(a.errorEvents).toBeGreaterThanOrEqual(1);
+    expect(a.errorRate).toBeGreaterThan(0);
+    expect(a.topModules.length).toBeGreaterThan(0);
+
+    const b = results.find(r => r.productId === 'product-b')!;
+    expect(b.totalEvents).toBeGreaterThanOrEqual(2);
+    expect(b.errorEvents).toBeGreaterThanOrEqual(1);
+  });
+
+  it('queryCrossProductDaily returns daily breakdown', async () => {
+    const results = await queryCrossProductDaily(['product-a', 'product-b']);
+
+    expect(results.length).toBeGreaterThan(0);
+    // Should have entries for both products
+    const productIds = new Set(results.map(r => r.productId));
+    expect(productIds.has('product-a')).toBe(true);
+    expect(productIds.has('product-b')).toBe(true);
+
+    // Verify date format
+    for (const r of results) {
+      expect(r.date).toMatch(/^\d{4}-\d{2}-\d{2}$/);
+      expect(r.count).toBeGreaterThan(0);
+    }
+  });
+
+  it('queryCrossProductClusters returns merged cluster list', async () => {
+    const clusters = await queryCrossProductClusters(['product-a', 'product-b'], 10);
+
+    expect(clusters.length).toBeGreaterThanOrEqual(2);
+    // Should be sorted by totalCount descending
+    for (let i = 1; i < clusters.length; i++) {
+      expect(clusters[i - 1].totalCount).toBeGreaterThanOrEqual(clusters[i].totalCount);
+    }
+  });
+
+  it('queryCrossProductSummary with date filter narrows results', async () => {
+    const results = await queryCrossProductSummary(
+      ['product-a'],
+      '2026-03-19T00:00:00.000Z',
+      '2026-03-19T23:59:59.000Z'
+    );
+
+    expect(results).toHaveLength(1);
+    const a = results[0];
+    // Only the March 19th events should be included
+    expect(a.totalEvents).toBeGreaterThanOrEqual(1);
+  });
+
+  it('queryCrossProductSummary for unknown product returns zero counts', async () => {
+    const results = await queryCrossProductSummary(['nonexistent-product']);
+
+    expect(results).toHaveLength(1);
+    expect(results[0].totalEvents).toBe(0);
+    expect(results[0].errorEvents).toBe(0);
+    expect(results[0].errorRate).toBe(0);
+  });
+
+  it('queryCrossProductClusters respects limit', async () => {
+    const clusters = await queryCrossProductClusters(['product-a', 'product-b'], 1);
+
+    expect(clusters).toHaveLength(1);
+    // Should be the highest count cluster
+    expect(clusters[0].totalCount).toBeGreaterThanOrEqual(3);
+  });
+});
diff --git a/services/platform-service/src/modules/telemetry/repository.ts b/services/platform-service/src/modules/telemetry/repository.ts
index e3344b76..a22d1d9b 100644
--- a/services/platform-service/src/modules/telemetry/repository.ts
+++ b/services/platform-service/src/modules/telemetry/repository.ts
@@ -214,3 +214,116 @@ export async function updateCluster(
     return null;
   }
 }
+
+// ─── Cross-Product Queries ──────────────────────────────────────────
+
+export interface CrossProductSummary {
+  productId: string;
+  totalEvents: number;
+  errorEvents: number;
+  errorRate: number;
+  topModules: Array<{ module: string; count: number }>;
+  platforms: Array<{ platform: string; count: number }>;
+}
+
+export interface DailyEventCount {
+  date: string;
+  productId: string;
+  count: number;
+}
+
+export async function queryCrossProductSummary(
+  productIds: string[],
+  from?: string,
+  to?: string
+): Promise<CrossProductSummary[]> {
+  const results: CrossProductSummary[] = [];
+
+  for (const productId of productIds) {
+    const filter: FilterMap = { productId };
+    if (from) filter.occurredAt = { ...((filter.occurredAt as object) ?? {}), $gte: from };
+    if (to) filter.occurredAt = { ...((filter.occurredAt as object) ?? {}), $lte: to };
+
+    const events = await eventsCollection().findMany({ filter, limit: 1000 });
+
+    const errorEvents = events.filter(e => ['warn', 'error', 'fatal'].includes(e.eventType));
+
+    // Aggregate modules
+    const moduleCounts: Record<string, number> = {};
+    for (const e of events) {
+      moduleCounts[e.module] = (moduleCounts[e.module] ?? 0) + 1;
+    }
+    const topModules = Object.entries(moduleCounts)
+      .map(([module, count]) => ({ module, count }))
+      .sort((a, b) => b.count - a.count)
+      .slice(0, 10);
+
+    // Aggregate platforms
+    const platformCounts: Record<string, number> = {};
+    for (const e of events) {
+      platformCounts[e.platform] = (platformCounts[e.platform] ?? 0) + 1;
+    }
+    const platforms = Object.entries(platformCounts)
+      .map(([platform, count]) => ({ platform, count }))
+      .sort((a, b) => b.count - a.count);
+
+    results.push({
+      productId,
+      totalEvents: events.length,
+      errorEvents: errorEvents.length,
+      errorRate: events.length > 0 ? errorEvents.length / events.length : 0,
+      topModules,
+      platforms,
+    });
+  }
+
+  return results;
+}
+
+export async function queryCrossProductDaily(
+  productIds: string[],
+  from?: string,
+  to?: string
+): Promise<DailyEventCount[]> {
+  const results: DailyEventCount[] = [];
+
+  for (const productId of productIds) {
+    const filter: FilterMap = { productId };
+    if (from) filter.occurredAt = { ...((filter.occurredAt as object) ?? {}), $gte: from };
+    if (to) filter.occurredAt = { ...((filter.occurredAt as object) ?? {}), $lte: to };
+
+    const events = await eventsCollection().findMany({ filter, limit: 1000 });
+
+    // Aggregate by date
+    const dayCounts: Record<string, number> = {};
+    for (const e of events) {
+      const date = e.occurredAt.substring(0, 10); // YYYY-MM-DD
+      dayCounts[date] = (dayCounts[date] ?? 0) + 1;
+    }
+
+    for (const [date, count] of Object.entries(dayCounts)) {
+      results.push({ date, productId, count });
+    }
+  }
+
+  return results.sort((a, b) => a.date.localeCompare(b.date));
+}
+
+export async function queryCrossProductClusters(
+  productIds: string[],
+  limit = 20
+): Promise<TelemetryErrorCluster[]> {
+  const allClusters: TelemetryErrorCluster[] = [];
+
+  for (const productId of productIds) {
+    const clusters = await clustersCollection().findMany({
+      filter: { productId },
+      sort: { totalCount: -1 },
+      limit,
+    });
+    allClusters.push(...clusters);
+  }
+
+  // Sort by totalCount descending and take top N
+  return allClusters.sort((a, b) => b.totalCount - a.totalCount).slice(0, limit);
+}
diff --git a/services/platform-service/src/modules/telemetry/routes.ts b/services/platform-service/src/modules/telemetry/routes.ts
index 7ad75621..34cbb15b 100644
--- a/services/platform-service/src/modules/telemetry/routes.ts
+++ b/services/platform-service/src/modules/telemetry/routes.ts
@@ -906,6 +906,37 @@ export async function telemetryRoutes(app: FastifyInstance) {
     return metrics;
   });
 
+  // ── Admin: cross-product telemetry ──────────────────────
+  app.get('/telemetry/cross-product', async req => {
+    requireAdmin(req);
+    const { products, from, to, limit } = req.query as {
+      products?: string;
+      from?: string;
+      to?: string;
+      limit?: string;
+    };
+
+    if (!products) {
+      throw new BadRequestError('products query parameter required (comma-separated productIds)');
+    }
+
+    const productIds = products
+      .split(',')
+      .map(p => p.trim())
+      .filter(Boolean);
+    if (productIds.length === 0 || productIds.length > 20) {
+      throw new BadRequestError('Provide 1-20 product IDs');
+    }
+
+    const [summary, daily, clusters] = await Promise.all([
+      repo.queryCrossProductSummary(productIds, from, to),
+      repo.queryCrossProductDaily(productIds, from, to),
+      repo.queryCrossProductClusters(productIds, limit ? parseInt(limit, 10) : 20),
+    ]);
+
+    return { summary, daily, clusters };
+  });
+
   // ── Prometheus OpenMetrics export ──────────────────────
   app.get('/telemetry/metrics/prometheus', async (req, reply) => {
     requireAdmin(req);