diff --git a/src/app/api/time-tracking/smartsheet-sync/route.ts b/src/app/api/time-tracking/smartsheet-sync/route.ts
new file mode 100644
index 0000000..b6ad393
--- /dev/null
+++ b/src/app/api/time-tracking/smartsheet-sync/route.ts
@@ -0,0 +1,159 @@
+/**
+ * Cron-driven Time Tracking Smartsheet sync drain.
+ *
+ * Cycle 8 — mirrors `/api/water-log/smartsheet-sync/route.ts` so
+ * closed clock-outs eventually land in the customer's Smartsheet
+ * workbook even when the worker loses connectivity between clock-out
+ * and the next realtime push.
+ *
+ * Hit by Vercel cron (see vercel.json entry: every 15 minutes). The
+ * per-frequency gating happens inside `runScheduledTTSync`:
+ *   - realtime:    the event-driven push in `clockOutWorker` covers
+ *                  most cases; the cron recovers anything that failed
+ *                  to enqueue or was retried out.
+ *   - every_15_min: drains the queue if last sync was ≥15m ago.
+ *   - hourly:      drains the queue if last sync was ≥60m ago.
+ *
+ * Auth:
+ *   - Bearer token in `Authorization: Bearer $CRON_SECRET` header,
+ *     or `?secret=$CRON_SECRET` query param (Vercel cron doesn't
+ *     support either natively; the header is what curl / external
+ *     schedulers use). Falls back to `CRON_SECRET` for cross-
+ *     compatibility with the existing automation routes.
+ *
+ * Body (optional):
+ *   - `{ brandId?: string }` — restrict to one brand (useful for the
+ *     "Retry now" admin button). If omitted, runs for every active
+ *     brand.
+ */
+import { NextRequest, NextResponse } from "next/server";
+import { eq } from "drizzle-orm";
+import { withPlatformAdmin } from "@/db/client";
+import { timeTrackingSmartsheetConfig } from "@/db/schema/time-tracking";
+import { runScheduledTTSync } from "@/services/time-tracking-smartsheet-sync";
+
+const CRON_SECRET =
+  process.env.SMARTSHEET_CRON_SECRET ?? process.env.CRON_SECRET ?? "";
+
+function unauthorized() {
+  return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+}
+
+function authenticate(req: NextRequest): boolean {
+  if (!CRON_SECRET) {
+    // No secret configured: refuse in prod, allow in dev so local
+    // debugging doesn't need a token.
+    return process.env.NODE_ENV !== "production";
+  }
+  const headerToken = req.headers
+    .get("authorization")
+    ?.replace(/^Bearer\s+/i, "");
+  const queryToken = new URL(req.url).searchParams.get("secret");
+  return headerToken === CRON_SECRET || queryToken === CRON_SECRET;
+}
+
+type BrandSummary = {
+  brandId: string;
+  considered: number;
+  synced: number;
+  skipped: number;
+  failed: number;
+  skippedReason?: string;
+  error?: string;
+};
+
+async function drainOneBrand(brandId: string): Promise<BrandSummary> {
+  try {
+    const result = await runScheduledTTSync(brandId);
+    // Discriminated union: TTDrainResult has `skipped: number`; the
+    // "skipped" branch has `skipped: true` (literal). The brand isn't
+    // due yet (hourly/15min gate) — return a zero summary so the
+    // totals stay clean.
+    if (result.skipped === true) {
+      return {
+        brandId,
+        considered: 0,
+        synced: 0,
+        skipped: 0,
+        failed: 0,
+        skippedReason: result.reason,
+      };
+    }
+    return {
+      brandId,
+      considered: result.considered,
+      synced: result.synced,
+      skipped: result.skipped,
+      failed: result.failed,
+    };
+  } catch (err) {
+    return {
+      brandId,
+      considered: 0,
+      synced: 0,
+      skipped: 0,
+      failed: 0,
+      error: (err as Error).message ?? "Unknown error",
+    };
+  }
+}
+
+// We need to enumerate every brand with a time-tracking smartsheet
+// config enabled. The workspace read happens inside
+// runScheduledTTSync, but we don't have a separate
+// `timeTrackingSmartsheetConfig` helper that lists "active" brands.
+// Instead, we ask Postgres directly via a raw query through
+// `withPlatformAdmin`.
+async function listActiveBrandIds(): Promise<string[]> {
+  return withPlatformAdmin(async (db) => {
+    const rows = await db
+      .select({ id: timeTrackingSmartsheetConfig.brandId })
+      .from(timeTrackingSmartsheetConfig)
+      .where(eq(timeTrackingSmartsheetConfig.syncEnabled, true));
+    return rows.map((r) => r.id);
+  });
+}
+
+export async function POST(req: NextRequest) {
+  if (!authenticate(req)) return unauthorized();
+
+  let body: { brandId?: string } = {};
+  try {
+    const text = await req.text();
+    if (text) body = JSON.parse(text);
+  } catch {
+    // ignore — body is optional
+  }
+
+  const start = Date.now();
+  const brandIds = body.brandId
+    ? [body.brandId]
+    : await listActiveBrandIds();
+
+  const results = await Promise.all(
+    brandIds.map((brandId) => drainOneBrand(brandId)),
+  );
+
+  const totals = results.reduce(
+    (acc, r) => ({
+      considered: acc.considered + r.considered,
+      synced: acc.synced + r.synced,
+      skipped: acc.skipped + r.skipped,
+      failed: acc.failed + r.failed,
+    }),
+    { considered: 0, synced: 0, skipped: 0, failed: 0 },
+  );
+
+  return NextResponse.json({
+    success: totals.failed === 0,
+    durationMs: Date.now() - start,
+    totals,
+    results,
+  });
+}
+
+// GET is also supported for easy browser testing during development.
+// Same auth; in production it should be POST-only.
+export async function GET(req: NextRequest) {
+  return POST(req);
+}
\ No newline at end of file
diff --git a/vercel.json b/vercel.json
index c6b3f25..93b76a5 100644
--- a/vercel.json
+++ b/vercel.json
@@ -25,6 +25,10 @@
       "path": "/api/water-log/smartsheet-sync",
       "schedule": "*/15 * * * *"
     },
+    {
+      "path": "/api/time-tracking/smartsheet-sync",
+      "schedule": "*/15 * * * *"
+    },
     {
       "path": "/api/email-automation/abandoned-cart",
       "schedule": "0 */6 * * *"