diff --git a/go/vehicle-gateway/internal/realtime/snapshot_writer.go b/go/vehicle-gateway/internal/realtime/snapshot_writer.go
index 4dfbb39e..41c70ec2 100644
--- a/go/vehicle-gateway/internal/realtime/snapshot_writer.go
+++ b/go/vehicle-gateway/internal/realtime/snapshot_writer.go
@@ -129,7 +129,10 @@ func (w *SnapshotWriter) Update(ctx context.Context, env envelope.FrameEnvelope)
 	eventTime := nullableTime(env.EventTimeMS)
 	receivedAt := nullableTime(env.ReceivedAtMS)
 	platformName := platformNameFromEnvelope(env)
-	parsedJSON := parsedJSONFromEnvelope(env)
+	parsedJSON, err := w.parsedJSONForEnvelope(ctx, env, vin)
+	if err != nil {
+		return err
+	}
 	if _, err = w.exec.ExecContext(ctx, upsertRealtimeSnapshotSQL,
 		string(env.Protocol),
 		vin,
@@ -167,6 +170,23 @@ func (w *SnapshotWriter) Update(ctx context.Context, env envelope.FrameEnvelope)
 	return err
 }
 
+func (w *SnapshotWriter) parsedJSONForEnvelope(ctx context.Context, env envelope.FrameEnvelope, vin string) (any, error) {
+	if len(env.Parsed) == 0 {
+		return nil, nil
+	}
+	parsed := cloneMap(env.Parsed)
+	if queryer, ok := w.exec.(Queryer); ok {
+		existing, err := realtimeSnapshotParsedJSON(ctx, queryer, env.Protocol, vin)
+		if err != nil {
+			return nil, err
+		}
+		if len(existing) > 0 {
+			parsed = mergeParsedForProtocol(env.Protocol, existing, env.Parsed)
+		}
+	}
+	return marshalParsedJSON(parsed), nil
+}
+
 func platformNameFromEnvelope(env envelope.FrameEnvelope) string {
 	if env.Fields != nil {
 		if value := strings.TrimSpace(stringValue(env.Fields["platform_account"])); value != "" {
@@ -193,11 +213,30 @@ func stringValue(value any) string {
 	}
 }
 
-func parsedJSONFromEnvelope(env envelope.FrameEnvelope) any {
-	if len(env.Parsed) == 0 {
+func realtimeSnapshotParsedJSON(ctx context.Context, queryer Queryer, protocol envelope.Protocol, vin string) (map[string]any, error) {
+	var raw sql.NullString
+	err := queryer.QueryRowContext(ctx, selectRealtimeSnapshotParsedJSONSQL, string(protocol), vin).Scan(&raw)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, nil
+		}
+		return nil, err
+	}
+	if !raw.Valid || strings.TrimSpace(raw.String) == "" {
+		return nil, nil
+	}
+	var parsed map[string]any
+	if err := json.Unmarshal([]byte(raw.String), &parsed); err != nil {
+		return nil, nil
+	}
+	return parsed, nil
+}
+
+func marshalParsedJSON(parsed map[string]any) any {
+	if len(parsed) == 0 {
 		return nil
 	}
-	data, err := json.Marshal(env.Parsed)
+	data, err := json.Marshal(parsed)
 	if err != nil {
 		return nil
 	}
@@ -436,6 +475,8 @@ ON DUPLICATE KEY UPDATE
   updated_at = IF(VALUES(event_time) IS NOT NULL AND (vehicle_realtime_snapshot.event_time IS NULL OR VALUES(event_time) >= vehicle_realtime_snapshot.event_time), CURRENT_TIMESTAMP, updated_at)
 `
 
+const selectRealtimeSnapshotParsedJSONSQL = `SELECT parsed_json FROM vehicle_realtime_snapshot WHERE protocol = ? AND vin = ?`
+
 const realtimeLocationTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_realtime_location (
   protocol VARCHAR(32) NOT NULL,
   vin VARCHAR(32) NOT NULL DEFAULT '',
diff --git a/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go b/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
index de296169..8f793ef1 100644
--- a/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
+++ b/go/vehicle-gateway/internal/realtime/snapshot_writer_test.go
@@ -3,6 +3,8 @@ package realtime
 import (
 	"context"
 	"database/sql"
+	"database/sql/driver"
+	"encoding/json"
 	"errors"
 	"strings"
 	"testing"
@@ -199,6 +201,52 @@ func TestSnapshotWriterUpsertsRealtimeLocationWhenCoordinatesExist(t *testing.T)
 	}
 }
 
+func TestSnapshotWriterMergesGB32960ParsedJSONAcrossSplitRealtimeFrames(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	writer := NewSnapshotWriter(db)
+
+	existing := `{"data_units":[{"type":"0x01","name":"vehicle","value":{"soc_percent":88}}]}`
+	mock.ExpectQuery("SELECT parsed_json FROM vehicle_realtime_snapshot WHERE protocol = \\? AND vin = \\?").
+		WithArgs("GB32960", "VIN001").
+		WillReturnRows(sqlmock.NewRows([]string{"parsed_json"}).AddRow(existing))
+	mock.ExpectExec("INSERT INTO vehicle_realtime_snapshot").
+		WithArgs(
+			"GB32960",
+			"VIN001",
+			"",
+			"",
+			"",
+			jsonDataUnitsArg{types: []string{"0x01", "0x30"}},
+			sqlmock.AnyArg(),
+			sqlmock.AnyArg(),
+			sqlmock.AnyArg(),
+		).
+		WillReturnResult(sqlmock.NewResult(0, 1))
+
+	err = writer.Update(context.Background(), envelope.FrameEnvelope{
+		Protocol:     envelope.ProtocolGB32960,
+		MessageID:    "0x02",
+		VIN:          "VIN001",
+		EventTimeMS:  1782918600000,
+		ReceivedAtMS: 1782918601000,
+		Parsed: map[string]any{
+			"data_units": []any{
+				map[string]any{"type": "0x30", "name": "gd_fc_stack", "value": map[string]any{"stack_count": 1}},
+			},
+		},
+	})
+	if err != nil {
+		t.Fatalf("Update() error = %v", err)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatalf("sql expectations: %v", err)
+	}
+}
+
 func TestRealtimeUpsertsDoNotOverwriteWithOlderEventTime(t *testing.T) {
 	for _, tc := range []struct {
 		name  string
@@ -588,3 +636,38 @@ func (r *recordingPlateResolver) PlateByVIN(_ context.Context, vin string) (stri
 	r.vin = vin
 	return r.plate, r.err
 }
+
+type jsonDataUnitsArg struct {
+	types []string
+}
+
+func (a jsonDataUnitsArg) Match(value driver.Value) bool {
+	text, ok := value.(string)
+	if !ok {
+		return false
+	}
+	var parsed map[string]any
+	if err := json.Unmarshal([]byte(text), &parsed); err != nil {
+		return false
+	}
+	units, ok := parsed["data_units"].([]any)
+	if !ok {
+		return false
+	}
+	seen := map[string]bool{}
+	for _, unit := range units {
+		unitMap, ok := unit.(map[string]any)
+		if !ok {
+			continue
+		}
+		if unitType, ok := unitMap["type"].(string); ok {
+			seen[unitType] = true
+		}
+	}
+	for _, unitType := range a.types {
+		if !seen[unitType] {
+			return false
+		}
+	}
+	return true
+}