diff --git a/backend/src/db.js b/backend/src/db.js
new file mode 100644
index 0000000..1ed30a0
--- /dev/null
+++ b/backend/src/db.js
@@ -0,0 +1,76 @@
+const Database = require('better-sqlite3');
+const bcrypt   = require('bcryptjs');
+const path     = require('path');
+
+const db = new Database(process.env.DB_PATH || '/data/dickendock.db');
+db.pragma('journal_mode = WAL');
+db.pragma('foreign_keys = ON');
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS users (
+    id            INTEGER PRIMARY KEY AUTOINCREMENT,
+    username      TEXT UNIQUE NOT NULL,
+    password_hash TEXT NOT NULL,
+    role          TEXT NOT NULL DEFAULT 'user',
+    created_at    DATETIME DEFAULT CURRENT_TIMESTAMP
+  );
+
+  -- Dashboard-Widgets
+  CREATE TABLE IF NOT EXISTS quick_links (
+    id         INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id    INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    title      TEXT NOT NULL,
+    url        TEXT NOT NULL,
+    icon       TEXT NOT NULL DEFAULT '🔗',
+    sort_order INTEGER DEFAULT 0
+  );
+  CREATE TABLE IF NOT EXISTS todos (
+    id         INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id    INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    text       TEXT NOT NULL,
+    done       INTEGER NOT NULL DEFAULT 0,
+    sort_order INTEGER DEFAULT 0,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+  );
+  CREATE TABLE IF NOT EXISTS notes (
+    id         INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id    INTEGER NOT NULL UNIQUE REFERENCES users(id) ON DELETE CASCADE,
+    content    TEXT NOT NULL DEFAULT '',
+    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
+  );
+
+  -- Tool: 3D-Kalkulator
+  CREATE TABLE IF NOT EXISTS calculations (
+    id                      INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id                 INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    name                    TEXT NOT NULL,
+    gramm                   REAL NOT NULL,
+    stunden                 REAL NOT NULL,
+    farben                  INTEGER NOT NULL DEFAULT 1,
+    materialpreis_pro_gramm REAL NOT NULL DEFAULT 0.01,
+    stromverbrauch_kw       REAL NOT NULL DEFAULT 0.15,
+    strompreis_pro_kwh      REAL NOT NULL DEFAULT 0.38,
+    druckerpreis            REAL NOT NULL DEFAULT 550,
+    gesamtdruckstunden      REAL NOT NULL DEFAULT 5000,
+    verschleiss_pro_stunde  REAL NOT NULL DEFAULT 0.06,
+    preis_freundschaft      REAL NOT NULL,
+    preis_normal            REAL NOT NULL,
+    preis_auftrag           REAL NOT NULL,
+    created_at              DATETIME DEFAULT CURRENT_TIMESTAMP,
+    updated_at              DATETIME DEFAULT CURRENT_TIMESTAMP
+  );
+`);
+
+// Standard-Admin beim ersten Start anlegen
+if (!db.prepare('SELECT id FROM users WHERE username = ?').get('admin')) {
+  db.prepare('INSERT INTO users (username, password_hash, role) VALUES (?, ?, ?)')
+    .run('admin', bcrypt.hashSync('admin123', 12), 'admin');
+  console.log('✅ Admin angelegt: admin / admin123  →  Bitte Passwort sofort ändern!');
+}
+
+// ── Migrationen (werden bei jedem Start geprüft) ─────────────────────────────
+const cols = db.prepare("PRAGMA table_info(calculations)").all().map(r => r.name);
+if (!cols.includes('image'))     db.exec("ALTER TABLE calculations ADD COLUMN image TEXT");
+if (!cols.includes('bemerkung')) db.exec("ALTER TABLE calculations ADD COLUMN bemerkung TEXT NOT NULL DEFAULT ''");
+
+module.exports = db;