diff --git a/backend/routes/availability.py b/backend/routes/availability.py
index a7dd35f..d4598b3 100644
--- a/backend/routes/availability.py
+++ b/backend/routes/availability.py
@@ -15,13 +15,11 @@ from schemas import (
     SetAvailabilityRequest,
     CopyAvailabilityRequest,
 )
+from shared_constants import MAX_ADVANCE_DAYS
 
 
 router = APIRouter(prefix="/api/admin/availability", tags=["availability"])
 
-# From shared/constants.json
-MAX_ADVANCE_DAYS = 30
-
 
 def _get_date_range_bounds() -> tuple[date, date]:
     """Get the valid date range for availability (tomorrow to +30 days)."""
diff --git a/backend/routes/booking.py b/backend/routes/booking.py
index 2981502..9421445 100644
--- a/backend/routes/booking.py
+++ b/backend/routes/booking.py
@@ -15,15 +15,11 @@ from schemas import (
     BookingRequest,
     AppointmentResponse,
 )
+from shared_constants import SLOT_DURATION_MINUTES, MIN_ADVANCE_DAYS, MAX_ADVANCE_DAYS
 
 
 router = APIRouter(prefix="/api/booking", tags=["booking"])
 
-# From shared/constants.json
-SLOT_DURATION_MINUTES = 15
-MIN_ADVANCE_DAYS = 1
-MAX_ADVANCE_DAYS = 30
-
 
 def _get_bookable_date_range() -> tuple[date, date]:
     """Get the valid date range for booking (tomorrow to +30 days)."""
diff --git a/backend/shared_constants.py b/backend/shared_constants.py
new file mode 100644
index 0000000..3a48651
--- /dev/null
+++ b/backend/shared_constants.py
@@ -0,0 +1,13 @@
+"""Load shared constants from shared/constants.json."""
+import json
+from pathlib import Path
+
+_constants_path = Path(__file__).parent.parent / "shared" / "constants.json"
+_constants = json.loads(_constants_path.read_text())
+
+# Booking constants
+SLOT_DURATION_MINUTES: int = _constants["booking"]["slotDurationMinutes"]
+MIN_ADVANCE_DAYS: int = _constants["booking"]["minAdvanceDays"]
+MAX_ADVANCE_DAYS: int = _constants["booking"]["maxAdvanceDays"]
+NOTE_MAX_LENGTH: int = _constants["booking"]["noteMaxLength"]
+