diff --git a/backend/handlers/bookings/reserve.go b/backend/handlers/bookings/reserve.go
index 7bbdad2..3af23d0 100644
--- a/backend/handlers/bookings/reserve.go
+++ b/backend/handlers/bookings/reserve.go
@@ -12,14 +12,15 @@ import (
 	"crussell/auth"
 	"crussell/db"
 	"crussell/handlers/scheduling"
+	"crussell/internal/validators"
 	"crussell/mw"
 	"net"
 )
 
 // ReserveSlotRequest represents the request body for reserving a slot
 type ReserveSlotRequest struct {
-	StartTime  time.Time `json:"start_time"`
-	ServiceIDs []string  `json:"service_ids"`
+	StartTime  time.Time `json:"start_time" validate:"required"`
+	ServiceIDs []string  `json:"service_ids" validate:"required,min=1"`
 }
 
 // ReserveSlotResponse represents the response for a successful reservation
@@ -41,6 +42,14 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if err := validators.Validate.Struct(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// M8
+	// L5
+
 	if req.StartTime.IsZero() {
 		http.Error(w, "start_time is required", http.StatusBadRequest)
 		return
@@ -51,15 +60,15 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// b. Extract client IP: check CF-Connecting-IP → X-Real-IP → X-Forwarded-For → RemoteAddr
-			ip := r.Header.Get("CF-Connecting-IP")
-			if ip == "" {
-				ip, _, _ = net.SplitHostPort(r.RemoteAddr)
-				if ip == "" {
-					ip = r.RemoteAddr
-				}
-			}
+	ip := r.Header.Get("CF-Connecting-IP")
+	if ip == "" {
+		ip, _, _ = net.SplitHostPort(r.RemoteAddr)
+		if ip == "" {
+			ip = r.RemoteAddr
+		}
+	}
 
-			// c. Detect auth: try context first, then parse Bearer token from Authorization header
+	// c. Detect auth: try context first, then parse Bearer token from Authorization header
 	userID, hasUser := r.Context().Value(mw.UserIDKey).(string)
 	hasAuth := hasUser && userID != ""
 
@@ -121,7 +130,7 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	endTime := req.StartTime.Add(time.Duration(svcDuration) * time.Minute)
 	var cnt int
 	db.DB.QueryRow(r.Context(), `
-		SELECT COUNT(*) FROM bookings WHERE status IN ('confirmed','in_progress','completed')
+		SELECT COUNT(*) FROM bookings WHERE status IN ('pending','confirmed','in_progress','completed')
 		AND start_time < $2
 		AND start_time + (INTERVAL '1 minute' * (
 			SELECT COALESCE(SUM(dur),60) FROM (
@@ -139,11 +148,11 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// h. Check time blocker overlap using scheduling.CheckTimeBlockerOverlap
-	blockerOverlap, blockerDesc, err := scheduling.CheckTimeBlockerOverlap(r.Context(), req.StartTime, endTime)
+	blockerOverlap, _, err := scheduling.CheckTimeBlockerOverlap(r.Context(), req.StartTime, endTime)
 	if err != nil {
 		log.Printf("Failed to check time blocker overlap: %v", err)
 	} else if blockerOverlap {
-		http.Error(w, fmt.Sprintf("Cannot book this time - slot is blocked: %s", blockerDesc), http.StatusConflict)
+		http.Error(w, "Cannot book this time - slot is blocked", http.StatusConflict)
 		return
 	}
 
@@ -152,8 +161,16 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	var createdAt time.Time
 
 	if hasAuth {
+		tx, err := db.DB.Begin(r.Context())
+		if err != nil {
+			log.Printf("Failed to start transaction: %v", err)
+			http.Error(w, "Internal server error", http.StatusInternalServerError)
+			return
+		}
+		defer tx.Rollback(r.Context())
+
 		// LOGGED IN: Delete existing reservation
-		_, err := db.DB.Exec(r.Context(), `
+		_, err = tx.Exec(r.Context(), `
 			DELETE FROM time_blockers
 			WHERE created_by = $1 AND description LIKE 'RESERVATION:user:%'
 		`, userID)
@@ -165,7 +182,7 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 
 		// Insert new reservation
 		description := fmt.Sprintf("RESERVATION:user:%s:%d", userID, time.Now().UnixNano())
-		err = db.DB.QueryRow(r.Context(), `
+		err = tx.QueryRow(r.Context(), `
 			INSERT INTO time_blockers (start_time, duration_minutes, description, created_by)
 			VALUES ($1, $2, $3, $4)
 			RETURNING id, created_at
@@ -175,6 +192,12 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 			http.Error(w, "Internal server error", http.StatusInternalServerError)
 			return
 		}
+
+		if err := tx.Commit(r.Context()); err != nil {
+			log.Printf("Failed to commit transaction: %v", err)
+			http.Error(w, "Internal server error", http.StatusInternalServerError)
+			return
+		}
 	} else {
 		// ANONYMOUS: Check cap (50 in 10 minutes)
 		tenMinutesAgo := time.Now().Add(-10 * time.Minute)
diff --git a/backend/handlers/bookings/reserve_test.go b/backend/handlers/bookings/reserve_test.go
index fd416bb..65f6fd9 100644
--- a/backend/handlers/bookings/reserve_test.go
+++ b/backend/handlers/bookings/reserve_test.go
@@ -1,5 +1,5 @@
-//go:build test
-// +build test
+//go:build test && dev
+// +build test,dev
 
 package bookings
 
@@ -43,7 +43,7 @@ func makeReserveRequest(method, path string, body interface{}, token string) *ht
 	// Add chi middleware stack for proper routing context
 	r := chi.NewRouter()
 	r.Use(middleware.RequestID)
-	r.Use(middleware.RealIP)
+	r.Use(middleware.ClientIPFromRemoteAddr)
 
 	if token != "" {
 		req.Header.Set("Authorization", "Bearer "+token)
@@ -398,7 +398,8 @@ func nextWeekday(weekday time.Weekday, loc *time.Location) time.Time {
 	if daysAhead < 2 {
 		daysAhead += 7
 	}
-	return now.AddDate(0, 0, daysAhead).Truncate(24 * time.Hour)
+	next := now.AddDate(0, 0, daysAhead)
+	return time.Date(next.Year(), next.Month(), next.Day(), 0, 0, 0, 0, next.Location())
 }
 
 // TestReserveSlot_WeekdayConversion verifies that Go's time.Weekday (0=Sunday)