diff --git a/fusion_clock/models/hr_employee.py b/fusion_clock/models/hr_employee.py
index 92844887..a347dd1f 100644
--- a/fusion_clock/models/hr_employee.py
+++ b/fusion_clock/models/hr_employee.py
@@ -47,6 +47,25 @@ class HrEmployee(models.Model):
         groups="fusion_clock.group_fusion_clock_manager",
     )
 
+    # NFC card (kiosk identification)
+    x_fclk_nfc_card_uid = fields.Char(
+        string='NFC Card UID',
+        index=True,
+        copy=False,
+        groups="fusion_clock.group_fusion_clock_manager",
+        help="Hex UID of the NFC card assigned to this employee. "
+             "Format: uppercase, colon-separated, e.g. 04:A2:B5:62:C1:80. "
+             "Same card the employee uses for door access.",
+    )
+
+    _sql_constraints = [
+        (
+            'fclk_nfc_card_uid_unique',
+            'UNIQUE(x_fclk_nfc_card_uid)',
+            'This NFC card is already assigned to another employee.',
+        ),
+    ]
+
     # On-time streak
     x_fclk_ontime_streak = fields.Integer(
         string='On-Time Streak',
diff --git a/fusion_clock/tests/__init__.py b/fusion_clock/tests/__init__.py
new file mode 100644
index 00000000..b18efb5d
--- /dev/null
+++ b/fusion_clock/tests/__init__.py
@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+
+from . import test_nfc_models
diff --git a/fusion_clock/tests/test_nfc_models.py b/fusion_clock/tests/test_nfc_models.py
new file mode 100644
index 00000000..74145ecc
--- /dev/null
+++ b/fusion_clock/tests/test_nfc_models.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+
+from odoo.tests.common import TransactionCase, tagged
+from odoo.exceptions import ValidationError
+from psycopg2 import IntegrityError
+from odoo.tools.misc import mute_logger
+
+
+@tagged('-at_install', 'post_install', 'fusion_clock')
+class TestNfcModels(TransactionCase):
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.Employee = cls.env['hr.employee']
+        cls.alice = cls.Employee.create({'name': 'Alice NFC', 'x_fclk_enable_clock': True})
+        cls.bob = cls.Employee.create({'name': 'Bob NFC', 'x_fclk_enable_clock': True})
+
+    def test_card_uid_is_writable(self):
+        self.alice.x_fclk_nfc_card_uid = '04:A2:B5:62:C1:80'
+        self.assertEqual(self.alice.x_fclk_nfc_card_uid, '04:A2:B5:62:C1:80')
+
+    def test_card_uid_is_unique_when_set(self):
+        self.alice.x_fclk_nfc_card_uid = '04:A2:B5:62:C1:80'
+        with self.assertRaises(IntegrityError), mute_logger('odoo.sql_db'):
+            with self.env.cr.savepoint():
+                self.bob.x_fclk_nfc_card_uid = '04:A2:B5:62:C1:80'
+                self.bob.flush_recordset(['x_fclk_nfc_card_uid'])
+
+    def test_card_uid_can_be_null_for_multiple_employees(self):
+        self.alice.x_fclk_nfc_card_uid = False
+        self.bob.x_fclk_nfc_card_uid = False
+        self.assertFalse(self.alice.x_fclk_nfc_card_uid)
+        self.assertFalse(self.bob.x_fclk_nfc_card_uid)