diff --git a/.replit b/.replit
index f28aea5..c50bc15 100644
--- a/.replit
+++ b/.replit
@@ -31,10 +31,6 @@ externalPort = 3002
 localPort = 43267
 externalPort = 3003
 
-[[ports]]
-localPort = 43839
-externalPort = 4200
-
 [env]
 PORT = "5000"
 
diff --git a/replit.md b/replit.md
index 6827afb..dfe6231 100644
--- a/replit.md
+++ b/replit.md
@@ -33,6 +33,8 @@ The database includes core tables for `users`, `guards`, `certifications`, `site
 **Recent Schema Updates (October 2025)**:
 - Service types now include specialized parameters: `fixedPostHours` (ore presidio fisso), `patrolPassages` (numero passaggi pattuglia), `inspectionFrequency` (frequenza ispezioni), `responseTimeMinutes` (tempo risposta pronto intervento)
 - Sites include service schedule fields: `serviceStartTime` and `serviceEndTime` (formato HH:MM)
+- **Contract Management**: Sites now include contract fields: `contractReference` (codice contratto), `contractStartDate`, `contractEndDate` (date validità contratto in formato YYYY-MM-DD)
+- Sites now reference service types via `serviceTypeId` foreign key; `shiftType` is optional and can be derived from service type
 
 ### API Endpoints
 Comprehensive RESTful API endpoints are provided for Authentication, Users, Guards, Sites, Shifts, and Notifications, supporting full CRUD operations with role-based access control.
@@ -49,7 +51,7 @@ Key frontend routes include `/`, `/guards`, `/sites`, `/shifts`, `/reports`, `/n
 ### Key Features
 - **Dashboard Operativa**: Live KPIs (active shifts, total guards, active sites, expiring certifications) and real-time shift status.
 - **Gestione Guardie**: Complete profiles with skill matrix (armed, fire safety, first aid, driver's license), certification management with automatic expiry, and unique badge numbers.
-- **Gestione Siti/Commesse**: Service types with specialized parameters (fixed post hours, patrol passages, inspection frequency, response time) and minimum requirements (guard count, armed, driver's license). Sites include service schedule (start/end time).
+- **Gestione Siti/Commesse**: Service types with specialized parameters (fixed post hours, patrol passages, inspection frequency, response time) and minimum requirements (guard count, armed, driver's license). Sites include service schedule (start/end time) and contract management (reference code, validity period with start/end dates). Contract status is visualized with badges (active/expiring/expired) and enforces shift creation only within active contract periods.
 - **Pianificazione Operativa Interattiva**: Three-step workflow for shift assignment:
   1. Select date → view uncovered sites with coverage status
   2. Select site → view filtered resources (guards and vehicles matching requirements)
diff --git a/shared/schema.ts b/shared/schema.ts
index c929854..496b098 100644
--- a/shared/schema.ts
+++ b/shared/schema.ts
@@ -205,7 +205,8 @@ export const sites = pgTable("sites", {
   location: locationEnum("location").notNull().default("roccapiemonte"), // Sede gestionale
   
   // Service requirements
-  shiftType: shiftTypeEnum("shift_type").notNull(),
+  serviceTypeId: varchar("service_type_id").references(() => serviceTypes.id),
+  shiftType: shiftTypeEnum("shift_type"), // Optional - can be derived from service type
   minGuards: integer("min_guards").notNull().default(1),
   requiresArmed: boolean("requires_armed").default(false),
   requiresDriverLicense: boolean("requires_driver_license").default(false),