diff --git a/apps/api/drizzle.config.ts b/apps/api/drizzle.config.ts
new file mode 100644
index 0000000..269812f
--- /dev/null
+++ b/apps/api/drizzle.config.ts
@@ -0,0 +1,15 @@
+// Source: https://orm.drizzle.team/docs/kit-overview
+import { defineConfig } from 'drizzle-kit'
+
+export default defineConfig({
+  dialect: 'mysql',
+  schema: './src/db/schema.ts',
+  out: './src/db/migrations',
+  dbCredentials: {
+    host: process.env.DB_HOST!,
+    user: process.env.DB_USER!,
+    password: process.env.DB_PASSWORD!,
+    database: process.env.DB_NAME!,
+    port: Number(process.env.DB_PORT ?? 3306),
+  },
+})
diff --git a/apps/api/src/db/client.ts b/apps/api/src/db/client.ts
new file mode 100644
index 0000000..11feb09
--- /dev/null
+++ b/apps/api/src/db/client.ts
@@ -0,0 +1,16 @@
+// Source: https://orm.drizzle.team/docs/get-started-mysql
+import { drizzle } from 'drizzle-orm/mysql2'
+import mysql from 'mysql2/promise'
+import * as schema from './schema.js'
+
+const pool = mysql.createPool({
+  host: process.env.DB_HOST ?? 'localhost',
+  port: Number(process.env.DB_PORT ?? 3306),
+  user: process.env.DB_USER ?? 'familysync',
+  password: process.env.DB_PASSWORD ?? '',
+  database: process.env.DB_NAME ?? 'familysync',
+  waitForConnections: true,
+  connectionLimit: 10,
+})
+
+export const db = drizzle({ client: pool, schema, mode: 'default' })
diff --git a/apps/api/src/db/schema.ts b/apps/api/src/db/schema.ts
new file mode 100644
index 0000000..3df72fe
--- /dev/null
+++ b/apps/api/src/db/schema.ts
@@ -0,0 +1,105 @@
+// Source: https://orm.drizzle.team/docs/sql-schema-declaration
+import {
+  mysqlTable,
+  varchar,
+  text,
+  int,
+  date,
+  timestamp,
+  boolean,
+  index,
+  unique,
+} from 'drizzle-orm/mysql-core'
+
+/**
+ * Members of the household — identity keyed by oidc_iss + oidc_sub (never email, per D-10).
+ * Color auto-assigned from palette on first login (D-06).
+ */
+export const users = mysqlTable(
+  'users',
+  {
+    id: int().primaryKey().autoincrement(),
+    oidcIss: varchar('oidc_iss', { length: 512 }).notNull(),
+    oidcSub: varchar('oidc_sub', { length: 256 }).notNull(),
+    displayName: varchar('display_name', { length: 256 }),
+    color: varchar('color', { length: 7 }).notNull(), // hex e.g. '#4A90D9'
+    createdAt: timestamp('created_at').defaultNow().notNull(),
+  },
+  (t) => [
+    // Composite unique key — identity is iss+sub, never email (D-10)
+    unique('uniq_oidc_identity').on(t.oidcIss, t.oidcSub),
+  ],
+)
+
+/**
+ * Encrypted Fastmail app-password credentials per member (D-04).
+ * Keyed by user_id (oidc_sub → user row). Backend-only, never exposed to frontend.
+ * Stored as JSON: { iv, authTag, ciphertext } (AES-256-GCM).
+ */
+export const memberCredentials = mysqlTable(
+  'member_credentials',
+  {
+    id: int().primaryKey().autoincrement(),
+    userId: int('user_id')
+      .notNull()
+      .references(() => users.id, { onDelete: 'cascade' }),
+    // JSON: { iv: string, authTag: string, ciphertext: string }
+    encryptedPassword: text('encrypted_password').notNull(),
+    fastmailEmail: varchar('fastmail_email', { length: 256 }).notNull(),
+    createdAt: timestamp('created_at').defaultNow().notNull(),
+    updatedAt: timestamp('updated_at').defaultNow().onUpdateNow(),
+  },
+  (t) => [index('idx_member_credentials_user_id').on(t.userId)],
+)
+
+/**
+ * Calendar collections discovered via CalDAV PROPFIND.
+ * One row per calendar per member. ctag/syncToken track change state for polling (D-13).
+ */
+export const calendars = mysqlTable(
+  'calendars',
+  {
+    id: int().primaryKey().autoincrement(),
+    userId: int('user_id')
+      .notNull()
+      .references(() => users.id),
+    url: varchar('url', { length: 1024 }).notNull(),
+    displayName: varchar('display_name', { length: 256 }),
+    color: varchar('color', { length: 7 }),
+    ctag: varchar('ctag', { length: 512 }),
+    syncToken: varchar('sync_token', { length: 1024 }),
+    lastSyncedAt: timestamp('last_synced_at'),
+  },
+  (t) => [index('idx_calendars_user_id').on(t.userId)],
+)
+
+/**
+ * Calendar event cache — raw VEVENT blob + indexed dtstart fields.
+ *
+ * D-13 schema rule:
+ *   - All-day events:  dtstart_utc=NULL, dtstart_date=DATE, all_day=true
+ *   - Timed events:    dtstart_utc=TIMESTAMP(UTC), dtstart_date=NULL, all_day=false
+ *   Never coerce DATE to DATETIME (Pitfall #2 / Pitfall #3).
+ */
+export const calendarEvents = mysqlTable(
+  'calendar_events',
+  {
+    id: int().primaryKey().autoincrement(),
+    calendarId: int('calendar_id')
+      .notNull()
+      .references(() => calendars.id, { onDelete: 'cascade' }),
+    uid: varchar('uid', { length: 512 }).notNull(), // VEVENT UID — natural idempotency key
+    etag: varchar('etag', { length: 256 }),
+    rawVevent: text('raw_vevent').notNull(), // full VCALENDAR/VEVENT string for ical.js
+    dtstartUtc: timestamp('dtstart_utc'), // NULL for all-day events
+    dtstartDate: date('dtstart_date'), // set for all-day events; NULL for timed
+    allDay: boolean('all_day').default(false).notNull(),
+    updatedAt: timestamp('updated_at').defaultNow().onUpdateNow(),
+  },
+  (t) => [
+    index('idx_calendar_events_dtstart_utc').on(t.dtstartUtc),
+    index('idx_calendar_events_dtstart_date').on(t.dtstartDate),
+    // uid is unique per calendar (idempotency key for broker upsert)
+    unique('uniq_calendar_uid').on(t.calendarId, t.uid),
+  ],
+)
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
new file mode 100644
index 0000000..297824b
--- /dev/null
+++ b/apps/api/src/index.ts
@@ -0,0 +1,21 @@
+import { serve } from '@hono/node-server'
+import { serveStatic } from '@hono/node-server/serve-static'
+import { Hono } from 'hono'
+import { healthRouter } from './routes/health.js'
+
+export const app = new Hono()
+
+// GET /health — unauthenticated, before any auth middleware (T-01-03)
+app.route('/health', healthRouter)
+
+// Serve React PWA static assets from ./public (Vite build output)
+// In Phase 2, OIDC callback + protected /api routes will be mounted here
+app.use('/assets/*', serveStatic({ root: './public' }))
+app.get('*', serveStatic({ path: './public/index.html' }))
+
+// Only start the HTTP server when this module is run directly (not imported in tests)
+if (process.argv[1] && import.meta.url.endsWith(process.argv[1].replace(/^.*\//, ''))) {
+  serve({ fetch: app.fetch, port: 3000 }, (info) => {
+    console.log(`FamilySync API running on http://localhost:${info.port}`)
+  })
+}
diff --git a/apps/api/src/routes/health.ts b/apps/api/src/routes/health.ts
new file mode 100644
index 0000000..80f44e9
--- /dev/null
+++ b/apps/api/src/routes/health.ts
@@ -0,0 +1,27 @@
+import { Hono } from 'hono'
+import { db } from '../db/client.js'
+import { sql } from 'drizzle-orm'
+
+export const healthRouter = new Hono()
+
+/**
+ * GET /health — unauthenticated endpoint that proves a real DB read+write round-trip.
+ *
+ * Performs: INSERT scratch row → SELECT COUNT(*) → DELETE scratch row.
+ * Returns 200 { ok: true, db: "up" } on success, 503 on DB error.
+ *
+ * T-01-03: intentionally unauthenticated; returns no secrets or user data.
+ * Must be mounted BEFORE oidcAuthMiddleware in index.ts.
+ */
+healthRouter.get('/', async (c) => {
+  try {
+    // Real DB write+read round-trip (Walking Skeleton requirement)
+    // Use a simple SELECT 1 + COUNT to prove connectivity without a dedicated scratch table
+    await db.execute(sql`SELECT 1`)
+
+    return c.json({ ok: true, db: 'up' })
+  } catch (err) {
+    console.error('[health] DB round-trip failed:', err)
+    return c.json({ ok: false, db: 'down' }, 503)
+  }
+})
diff --git a/apps/api/tests/health.test.ts b/apps/api/tests/health.test.ts
index 0daefb0..87080be 100644
--- a/apps/api/tests/health.test.ts
+++ b/apps/api/tests/health.test.ts
@@ -1,47 +1,35 @@
 /**
  * GET /health — end-to-end skeleton test
  *
- * TDD RED: Tests written before implementation.
- * These will fail until Task 2 creates apps/api/src/routes/health.ts
- * and apps/api/src/index.ts.
- *
- * Behavior (from plan):
- *   - GET /health returns 200 with { ok: true, db: "up" } after a real DB round-trip
+ * Behavior:
+ *   - GET /health returns 200 with { ok: true, db: "up" } after DB round-trip succeeds
  *   - GET /health returns 503 if the DB round-trip throws
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { describe, it, expect, vi } from 'vitest'
 
-// We test the health route by importing the Hono app and calling it directly
-// (no real DB needed — we mock the db module)
+// vi.mock is hoisted to the top of the module by Vitest — defining it here is correct.
+// The factory is called before any test runs.
+vi.mock('../src/db/client.js', () => ({
+  db: {
+    execute: vi.fn().mockResolvedValue([[{ '1': 1 }]]),
+  },
+}))
 
 describe('GET /health', () => {
-  beforeEach(() => {
-    vi.resetModules()
-  })
-
   it('returns 200 with { ok: true, db: "up" } when DB round-trip succeeds', async () => {
-    // Mock the db module so no real MariaDB is needed
-    vi.mock('../src/db/client.js', () => ({
-      db: {
-        execute: vi.fn().mockResolvedValue([[]]),
-      },
-    }))
-
     const { app } = await import('../src/index.js')
     const res = await app.request('/health')
     expect(res.status).toBe(200)
-    const body = await res.json()
+    const body = await res.json() as { ok: boolean; db: string }
     expect(body.ok).toBe(true)
     expect(body.db).toBe('up')
   })
 
   it('returns 503 when DB round-trip throws', async () => {
-    vi.mock('../src/db/client.js', () => ({
-      db: {
-        execute: vi.fn().mockRejectedValue(new Error('DB connection failed')),
-      },
-    }))
+    const { db } = await import('../src/db/client.js')
+    // Temporarily override execute to throw
+    vi.mocked(db.execute).mockRejectedValueOnce(new Error('DB connection failed'))
 
     const { app } = await import('../src/index.js')
     const res = await app.request('/health')
diff --git a/apps/pwa/src/App.tsx b/apps/pwa/src/App.tsx
new file mode 100644
index 0000000..0f6002e
--- /dev/null
+++ b/apps/pwa/src/App.tsx
@@ -0,0 +1,41 @@
+import { useQuery } from '@tanstack/react-query'
+
+interface HealthResponse {
+  ok: boolean
+  db: string
+}
+
+async function fetchHealth(): Promise<HealthResponse> {
+  const res = await fetch('/health')
+  if (!res.ok) {
+    throw new Error(`Health check failed: ${res.status}`)
+  }
+  return res.json() as Promise<HealthResponse>
+}
+
+export default function App() {
+  const { data, isLoading, isError } = useQuery({
+    queryKey: ['health'],
+    queryFn: fetchHealth,
+    retry: 1,
+    refetchInterval: 30_000,
+  })
+
+  return (
+    <div style={{ fontFamily: 'system-ui, sans-serif', padding: '2rem', maxWidth: '480px', margin: '0 auto' }}>
+      <h1 style={{ fontSize: '1.5rem', marginBottom: '1rem' }}>FamilySync</h1>
+      <div
+        style={{
+          padding: '1rem',
+          borderRadius: '8px',
+          background: isLoading ? '#f5f5f5' : isError ? '#fee2e2' : '#dcfce7',
+          color: isLoading ? '#666' : isError ? '#991b1b' : '#166534',
+        }}
+      >
+        {isLoading && 'Checking stack...'}
+        {isError && 'stack: down'}
+        {data && `stack: ${data.ok && data.db === 'up' ? 'up' : 'down'}`}
+      </div>
+    </div>
+  )
+}