diff --git a/connector_whatsapp.go b/connector_whatsapp.go
index 306ef3f..8d4bded 100644
--- a/connector_whatsapp.go
+++ b/connector_whatsapp.go
@@ -144,9 +144,15 @@ func (w *WhatsAppConnector) FetchNew() ([]UnifiedMessage, error) {
 		return nil, err
 	}
 
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
 	var result []UnifiedMessage
 	for _, msg := range messages {
-		// WhatsApp bridge doesn't track seen status, so return all recent
+		// Skip if already marked as seen
+		if w.lastSeen[msg.ID] {
+			continue
+		}
 		// Filter to last 24 hours for "new"
 		if time.Since(msg.Timestamp) < 24*time.Hour {
 			result = append(result, w.convertMessage(msg))