diff --git a/backend/api/handlers.go b/backend/api/handlers.go
index ee55ec8..33f68d6 100644
--- a/backend/api/handlers.go
+++ b/backend/api/handlers.go
@@ -257,7 +257,7 @@ func (h *Handler) heartbeat(w http.ResponseWriter, r *http.Request) {
 		h.db.UpdateAgentAPIKey(req.AgentID, keyInfo.Key)
 	}
 
-	if err := h.db.SaveSystemData(req.AgentID, &req.SystemData); err != nil {
+	if err := h.db.SaveSystemDataRaw(req.AgentID, req.SystemData); err != nil {
 		if strings.Contains(err.Error(), "nicht gefunden") {
 			writeError(w, http.StatusNotFound, "Agent nicht gefunden")
 			return
diff --git a/backend/db/postgres.go b/backend/db/postgres.go
index f411107..9f9c21e 100644
--- a/backend/db/postgres.go
+++ b/backend/db/postgres.go
@@ -354,6 +354,52 @@ func (d *Database) RegisterAgent(agent *models.Agent) error {
 	return err
 }
 
+// SaveSystemDataRaw speichert rohe JSON-Systemdaten (plattformunabhaengig)
+func (d *Database) SaveSystemDataRaw(agentID string, raw json.RawMessage) error {
+	now := time.Now().UTC()
+
+	// Leeres JSON als leeres Objekt behandeln
+	if len(raw) == 0 {
+		raw = json.RawMessage("{}")
+	}
+
+	tx, err := d.db.Begin()
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+
+	res, err := tx.Exec("UPDATE agents SET last_heartbeat = $1 WHERE id = $2", now, agentID)
+	if err != nil {
+		return err
+	}
+	rows, _ := res.RowsAffected()
+	if rows == 0 {
+		return fmt.Errorf("Agent %s nicht gefunden", agentID)
+	}
+
+	_, err = tx.Exec(`
+		INSERT INTO system_data (agent_id, data_json, updated_at)
+		VALUES ($1, $2, $3)
+		ON CONFLICT(agent_id) DO UPDATE SET
+			data_json=EXCLUDED.data_json,
+			updated_at=EXCLUDED.updated_at
+	`, agentID, string(raw), now)
+	if err != nil {
+		return err
+	}
+
+	// Metriken nur fuer OPNsense/Linux (haben bekannte Struct-Form)
+	var sd models.SystemData
+	if err2 := json.Unmarshal(raw, &sd); err2 == nil && sd.CPU.Threads > 0 {
+		if err2 := d.writeMetrics(tx, agentID, now, &sd); err2 != nil {
+			log.Printf("Metriken schreiben Warnung: %v", err2)
+		}
+	}
+
+	return tx.Commit()
+}
+
 func (d *Database) SaveSystemData(agentID string, data *models.SystemData) error {
 	now := time.Now().UTC()
 
diff --git a/backend/models/system.go b/backend/models/system.go
index 6ef805c..49453cc 100644
--- a/backend/models/system.go
+++ b/backend/models/system.go
@@ -1,5 +1,7 @@
 package models
 
+import "encoding/json"
+
 // SystemData - Alle Systemdaten die der Agent sendet
 type SystemData struct {
 	AgentID           string             `json:"agent_id"`
@@ -291,10 +293,10 @@ type CaddyData struct {
 
 // HeartbeatRequest
 type HeartbeatRequest struct {
-	AgentID      string     `json:"agent_id"`
-	AgentVersion string     `json:"agent_version,omitempty"`
-	Platform     string     `json:"platform,omitempty"`
-	SystemData   SystemData `json:"system_data"`
+	AgentID      string          `json:"agent_id"`
+	AgentVersion string          `json:"agent_version,omitempty"`
+	Platform     string          `json:"platform,omitempty"`
+	SystemData   json.RawMessage `json:"system_data"`
 }
 
 // HeartbeatResponse