diff --git a/server/db.ts b/server/db.ts
new file mode 100644
index 0000000..948dcf0
--- /dev/null
+++ b/server/db.ts
@@ -0,0 +1,111 @@
+import Database from 'better-sqlite3'
+import { drizzle } from 'drizzle-orm/better-sqlite3'
+import { sqliteTable, text, integer } from 'drizzle-orm/sqlite-core'
+import path from 'path'
+import fs from 'fs'
+
+const DB_PATH = process.env.DB_PATH || path.join(process.cwd(), 'data', 'app.db')
+fs.mkdirSync(path.dirname(DB_PATH), { recursive: true })
+
+const sqlite = new Database(DB_PATH)
+sqlite.pragma('journal_mode = WAL')
+sqlite.pragma('foreign_keys = ON')
+
+export const db = drizzle(sqlite)
+
+export const users = sqliteTable('users', {
+  id:           text('id').primaryKey(),
+  username:     text('username').notNull().unique(),
+  passwordHash: text('password_hash').notNull(),
+  cloudEnabled: integer('cloud_enabled', { mode: 'boolean' }).notNull().default(false),
+  createdAt:    integer('created_at').notNull(),
+})
+
+export const notes = sqliteTable('notes', {
+  id:        text('id').primaryKey(),
+  userId:    text('user_id').notNull().references(() => users.id),
+  title:     text('title').notNull().default(''),
+  content:   text('content').notNull().default(''),
+  folderId:  text('folder_id'),
+  tags:      text('tags').notNull().default('[]'),
+  starred:   integer('starred', { mode: 'boolean' }).notNull().default(false),
+  wordCount: integer('word_count').notNull().default(0),
+  deletedAt: integer('deleted_at'),
+  createdAt: integer('created_at').notNull(),
+  updatedAt: integer('updated_at').notNull(),
+})
+
+export const folders = sqliteTable('folders', {
+  id:        text('id').primaryKey(),
+  userId:    text('user_id').notNull().references(() => users.id),
+  name:      text('name').notNull(),
+  parentId:  text('parent_id'),
+  order:     integer('order').notNull().default(0),
+  createdAt: integer('created_at').notNull(),
+})
+
+export const comments = sqliteTable('comments', {
+  id:        text('id').primaryKey(),
+  userId:    text('user_id').notNull().references(() => users.id),
+  content:   text('content').notNull(),
+  createdAt: integer('created_at').notNull(),
+})
+
+export const inviteCodes = sqliteTable('invite_codes', {
+  code:         text('code').primaryKey(),
+  usedByUserId: text('used_by_user_id'),
+  usedAt:       integer('used_at'),
+})
+
+export function initDb() {
+  sqlite.exec(`
+    CREATE TABLE IF NOT EXISTS users (
+      id TEXT PRIMARY KEY,
+      username TEXT UNIQUE NOT NULL,
+      password_hash TEXT NOT NULL,
+      cloud_enabled INTEGER NOT NULL DEFAULT 0,
+      created_at INTEGER NOT NULL
+    );
+    CREATE TABLE IF NOT EXISTS notes (
+      id TEXT PRIMARY KEY,
+      user_id TEXT NOT NULL REFERENCES users(id),
+      title TEXT NOT NULL DEFAULT '',
+      content TEXT NOT NULL DEFAULT '',
+      folder_id TEXT,
+      tags TEXT NOT NULL DEFAULT '[]',
+      starred INTEGER NOT NULL DEFAULT 0,
+      word_count INTEGER NOT NULL DEFAULT 0,
+      deleted_at INTEGER,
+      created_at INTEGER NOT NULL,
+      updated_at INTEGER NOT NULL
+    );
+    CREATE TABLE IF NOT EXISTS folders (
+      id TEXT PRIMARY KEY,
+      user_id TEXT NOT NULL REFERENCES users(id),
+      name TEXT NOT NULL,
+      parent_id TEXT,
+      "order" INTEGER NOT NULL DEFAULT 0,
+      created_at INTEGER NOT NULL
+    );
+    CREATE TABLE IF NOT EXISTS comments (
+      id TEXT PRIMARY KEY,
+      user_id TEXT NOT NULL REFERENCES users(id),
+      content TEXT NOT NULL,
+      created_at INTEGER NOT NULL
+    );
+    CREATE TABLE IF NOT EXISTS invite_codes (
+      code TEXT PRIMARY KEY,
+      used_by_user_id TEXT,
+      used_at INTEGER
+    );
+  `)
+
+  const INVITE_CODES = [
+    'MIKI-A7X2-KP9Q', 'MIKI-B3N8-WR4L', 'MIKI-C6M1-ZT7Y',
+    'MIKI-D9F5-HJ2V', 'MIKI-E4K3-QN6U', 'MIKI-F8R7-XG1S',
+    'MIKI-G2W4-LB5E', 'MIKI-H5T9-MC8D', 'MIKI-J1P6-VF3O',
+    'MIKI-K7Q2-YH4N',
+  ]
+  const insert = sqlite.prepare(`INSERT OR IGNORE INTO invite_codes (code) VALUES (?)`)
+  for (const code of INVITE_CODES) insert.run(code)
+}