diff --git a/docs/QA_PLAN.md b/docs/QA_PLAN.md
index 95a05d7..b2e184d 100644
--- a/docs/QA_PLAN.md
+++ b/docs/QA_PLAN.md
@@ -102,7 +102,7 @@ before cross-cutting; regression last). Update **Status** and **Findings** every
 | B12 | Settings, Profile & global UI | `/settings`, `/profile`, static pages, command palette, sidebar/nav | any | ⬜ | 0 / 0 |
 | B13 | API / backend direct | all `/api/*`: auth, CSRF, validation, rate limits, error shape, IDOR, cents | via HTTP client | 🔄 | 0 / 1 |
 | B14 | Non-functional | a11y, performance, PWA/offline, XSS/secrets, timezone/DST | large + adversarial | 🔄 | 0 / 3 |
-| B15 | Regression & sign-off | full smoke on **production build**, exit criteria | seeded | ⬜ | 0 / 0 |
+| B15 | Regression & sign-off | full smoke on **production build**, exit criteria | seeded | 🔄 | 0 / 0 |
 
 > After B15, if any batch is 🔁 or has open S1/S2, loop back. Then start a new
 > cycle from B0 against the next build/version.
@@ -231,6 +231,7 @@ Manual passes prove a button works **once**; they don't stop it regressing next
 | `npm run test:e2e` | run the E2E suite headless (boots the app via `webServer`) |
 | `npm run test:e2e:ui` | Playwright UI mode — watch/debug interactively |
 | `npm run test:e2e:update` | re-baseline visual-regression screenshots (review the diff before committing) |
+| `npm run smoke:prod` | **B15 production-build smoke** — builds, boots `node server.js` (dist/), drives the real artifact so the split vendor chunks are validated at runtime |
 
 - **Setup (one-time):** `npm install` then `npx playwright install chromium`. Config: `playwright.config.js`; specs in `e2e/`.
 - **Scope:** the suite is a **thin critical-path smoke**, not a replacement for the manual playbooks — it locks the happy paths (login → pay bill → skip → note → reconcile), the primitive state matrix, per-page axe scans, and page screenshots. Grow it whenever a manual pass finds a UI regression that a click-test could have caught.
diff --git a/package.json b/package.json
index b80b0bb..060aa9d 100644
--- a/package.json
+++ b/package.json
@@ -17,6 +17,7 @@
     "test:e2e:ui": "node e2e/setup/prepare-db.js && playwright test --ui",
     "test:e2e:update": "node e2e/setup/prepare-db.js && playwright test --project=chromium-desktop --project=chromium-mobile --update-snapshots",
     "test:e2e:probe": "node e2e/setup/prepare-db.js && playwright test --project=probe",
+    "smoke:prod": "bash scripts/prod-smoke.sh",
     "ci": "npm run check:server && npm run test:all && npm run build",
     "start": "node server.js"
   },
diff --git a/scripts/prod-smoke.js b/scripts/prod-smoke.js
new file mode 100644
index 0000000..f2f29de
--- /dev/null
+++ b/scripts/prod-smoke.js
@@ -0,0 +1,68 @@
+#!/usr/bin/env node
+/**
+ * Production-build smoke (QA_PLAN B15). Drives the REAL built artifact — `node
+ * server.js` serving dist/ — not the Vite dev server, so it validates that the
+ * split vendor chunks (QA-B0-01) actually load and the app boots in production.
+ *
+ * Usage: node scripts/prod-smoke.js   (expects `npm run build` already run and a
+ * server already listening on PROD_SMOKE_URL — the shell wrapper handles both).
+ */
+const { chromium } = require('@playwright/test');
+
+const URL = process.env.PROD_SMOKE_URL || 'http://localhost:3098';
+const USER = process.env.E2E_USER || 'e2e_user';
+const PASS = process.env.E2E_PASS || 'e2e_pass_1234';
+
+(async () => {
+  const browser = await chromium.launch();
+  const page = await browser.newPage();
+  const errors = [];
+  const failed = [];
+  page.on('console', (m) => { if (m.type() === 'error') errors.push(m.text()); });
+  page.on('pageerror', (e) => errors.push(String(e)));
+  page.on('requestfailed', (r) => failed.push(`${r.url()} ${r.failure()?.errorText || ''}`));
+
+  let ok = true;
+  const fail = (msg) => { ok = false; console.error('  ✖', msg); };
+
+  try {
+    // 1. App shell + split chunks load; login page renders.
+    await page.goto(URL + '/login', { waitUntil: 'networkidle' });
+    const heading = page.getByRole('heading', { name: /sign in/i });
+    if (await heading.isVisible().catch(() => false)) console.log('  ✔ login page renders (vendor chunks loaded)');
+    else fail('login page did not render — a chunk may have failed to load');
+
+    // 2. Log in and reach the authenticated app (lazy route chunks load).
+    await page.locator('#username').fill(USER);
+    await page.locator('#password').fill(PASS);
+    await page.getByRole('button', { name: /sign in/i }).click();
+    await page.waitForURL((u) => !u.pathname.startsWith('/login'), { timeout: 15000 });
+    const gotIt = page.getByRole('button', { name: 'Got it' });
+    await gotIt.click({ timeout: 8000 }).catch(() => {});
+    if (await page.getByRole('button', { name: 'Add Bill' }).isVisible().catch(() => false)) {
+      console.log('  ✔ authenticated Tracker renders on the production build');
+    } else fail('authenticated Tracker did not render');
+
+    // 3. A couple of lazy-loaded routes render (their chunks resolve).
+    for (const path of ['/bills', '/analytics', '/spending']) {
+      await page.goto(URL + path, { waitUntil: 'networkidle' });
+      const empty = await page.locator('body').innerText().catch(() => '');
+      if (empty && empty.trim().length > 0) console.log(`  ✔ ${path} rendered`);
+      else fail(`${path} rendered blank (lazy chunk failure?)`);
+    }
+  } catch (e) {
+    fail('exception: ' + e.message);
+  }
+
+  const chunkErrors = failed.filter((f) => /\.js|\.css|assets/.test(f));
+  if (chunkErrors.length) fail('failed asset requests:\n    ' + chunkErrors.join('\n    '));
+  // The pre-login page probes /api/auth/session and gets 401 by design (then shows
+  // login) — that's expected, not a defect. Everything else is a real error.
+  const benign = /session check failed|Not authenticated|auth\/session|status of 401/i;
+  const realErrors = errors.filter((e) => !benign.test(e));
+  if (realErrors.length) fail('console/page errors:\n    ' + realErrors.slice(0, 5).join('\n    '));
+
+  await browser.close();
+  console.log(ok ? '\nPROD SMOKE: PASS' : '\nPROD SMOKE: FAIL');
+  process.exit(ok ? 0 : 1);
+})();
diff --git a/scripts/prod-smoke.sh b/scripts/prod-smoke.sh
new file mode 100755
index 0000000..135eadf
--- /dev/null
+++ b/scripts/prod-smoke.sh
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Production-build smoke (QA_PLAN B15): builds the app, boots `node server.js`
+# serving dist/ against a scratch DB, and drives the real artifact with Playwright
+# to confirm the split vendor chunks load and the app works in production.
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+PORT="${PROD_SMOKE_PORT:-3098}"
+export PROD_SMOKE_URL="http://localhost:${PORT}"
+
+echo "[prod-smoke] building…"
+npm run build >/dev/null
+
+echo "[prod-smoke] preparing scratch DB…"
+node e2e/setup/prepare-db.js >/dev/null 2>&1
+
+echo "[prod-smoke] starting production server on :${PORT}…"
+DB_PATH="db/e2e.db" PORT="${PORT}" BIND_HOST=127.0.0.1 node server.js >/tmp/prod-smoke-server.log 2>&1 &
+SRV=$!
+trap 'kill "${SRV}" 2>/dev/null || true' EXIT
+
+for _ in $(seq 1 40); do
+  curl -sf "http://localhost:${PORT}/api/version" >/dev/null 2>&1 && break
+  sleep 0.5
+done
+
+node scripts/prod-smoke.js