diff --git a/operations.go b/operations.go
index 5e443c1..f68cf88 100644
--- a/operations.go
+++ b/operations.go
@@ -10,22 +10,24 @@ import (
 
 type writerF func(string, string, interface{}, int) (gocb.Cas, error)
 type readerF func(string, string, interface{}, int) (gocb.Cas, error)
+type Cas map[string]gocb.Cas
 
-func (h *Handler) Insert(ctx context.Context, typ, id string, q interface{}) (string, error) {
+func (h *Handler) Insert(ctx context.Context, typ, id string, q interface{}) (Cas, string, error) {
+	cas := make(map[string]gocb.Cas)
 	if id == "" {
 		id = xid.New().String()
 	}
 	id, err := h.write(ctx, typ, id, q, func(typ, id string, ptr interface{}, ttl int) (gocb.Cas, error) {
 		documentID := typ + "::" + id
 		return h.state.bucket.Insert(documentID, ptr, 0)
-	})
+	}, cas)
 	if err != nil {
-		return "", err
+		return nil, "", err
 	}
-	return id, nil
+	return cas, id, nil
 }
 
-func (h *Handler) write(ctx context.Context, typ, id string, q interface{}, f writerF) (string, error) {
+func (h *Handler) write(ctx context.Context, typ, id string, q interface{}, f writerF, cas Cas) (string, error) {
 	if !h.state.inspect(typ) {
 		err := h.state.setType(typ, typ)
 		if err != nil {
@@ -61,7 +63,7 @@ func (h *Handler) write(ctx context.Context, typ, id string, q interface{}, f wr
 					if refTag == "" {
 						return "", ErrEmptyRefTag
 					}
-					if _, err := h.write(ctx, refTag, id, rvQField.Interface(), f); err != nil {
+					if _, err := h.write(ctx, refTag, id, rvQField.Interface(), f, cas); err != nil {
 						return id, err
 					}
 				} else {
@@ -72,7 +74,9 @@ func (h *Handler) write(ctx context.Context, typ, id string, q interface{}, f wr
 			}
 		}
 	}
-	_, err := f(typ, id, fields, -1)
+	c, err := f(typ, id, fields, -1)
+	cas[typ] = c
+
 	return id, err
 }
 
@@ -139,18 +143,19 @@ func (h *Handler) Remove(ctx context.Context, typ, id string, ptr interface{}) e
 	return nil
 }
 
-func (h *Handler) Upsert(ctx context.Context, typ, id string, q interface{}, ttl uint32) (string, error) {
+func (h *Handler) Upsert(ctx context.Context, typ, id string, q interface{}, ttl uint32) (Cas, string, error) {
+	cas := make(map[string]gocb.Cas)
 	if id == "" {
 		id = xid.New().String()
 	}
 	id, err := h.write(ctx, typ, id, q, func(typ, id string, q interface{}, ttl int) (gocb.Cas, error) {
 		documentID := typ + "::" + id
 		return h.state.bucket.Upsert(documentID, q, uint32(ttl))
-	})
+	}, cas)
 	if err != nil {
-		return "", err
+		return nil, "", err
 	}
-	return id, nil
+	return cas, id, nil
 
 }
 
diff --git a/operations_test.go b/operations_test.go
index fcf213d..06728ca 100644
--- a/operations_test.go
+++ b/operations_test.go
@@ -32,7 +32,7 @@ func TestInsertNullString(t *testing.T) {
 		IssuingBank: "",
 		CardType:    null.String{String: "US", Valid: true},
 	}
-	_, err := th.Insert(context.Background(), "card_type", "", cardTypeWrite)
+	_, _, err := th.Insert(context.Background(), "card_type", "", cardTypeWrite)
 	if err != nil {
 		t.Error(err)
 	}
@@ -42,7 +42,7 @@ func TestInsertNullString(t *testing.T) {
 func TestInsertCustomID(t *testing.T) {
 	cID := xid.New().String() + "Faswwq123942390**12312_+"
 	ws := generate()
-	id, err := th.Insert(context.Background(), "webshop", cID, &ws)
+	_, id, err := th.Insert(context.Background(), "webshop", cID, &ws)
 	if err != nil {
 		t.Error(err)
 	}
@@ -51,10 +51,13 @@ func TestInsertCustomID(t *testing.T) {
 
 func TestInsertPtrValue(t *testing.T) {
 	ws := generate()
-	id, err := th.Insert(context.Background(), "webshop", "", &ws)
+	cas, id, err := th.Insert(context.Background(), "webshop", "", &ws)
 	if err != nil || id == "" {
 		t.Fatal(err)
 	}
+	if len(cas) != 3 {
+		t.Errorf("Cas should store 3 elements, instead of %d", len(cas))
+	}
 }
 
 func TestInsertPrimitivePtr(t *testing.T) {
@@ -62,30 +65,39 @@ func TestInsertPrimitivePtr(t *testing.T) {
 	s := struct {
 		Name *string `json:"name,omitempty"`
 	}{Name: &asd}
-	id, err := th.Insert(context.Background(), "webshop", "", s)
+	cas, id, err := th.Insert(context.Background(), "webshop", "", s)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+	}
 }
 
 func TestInsertPrimitivePtrNil(t *testing.T) {
 	s := struct {
 		Name *string `json:"name,omitempty"`
 	}{}
-	id, err := th.Insert(context.Background(), "webshop", "", s)
+	cas, id, err := th.Insert(context.Background(), "webshop", "", s)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+	}
 }
 
 func TestInsertNonExportedField(t *testing.T) {
 	s := struct {
 		name string
 	}{name: "Jackson"}
-	id, err := th.Insert(context.Background(), "member", "", s)
+	cas, id, err := th.Insert(context.Background(), "member", "", s)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+	}
 }
 
 func TestInsertExpectDuplicateError(t *testing.T) {
@@ -94,11 +106,11 @@ func TestInsertExpectDuplicateError(t *testing.T) {
 	}{name: "Jackson"}
 	ctx := context.Background()
 	id := xid.New().String()
-	_, err := th.Insert(ctx, "member", id, s)
+	_, _, err := th.Insert(ctx, "member", id, s)
 	if err != nil {
 		t.Error("Missing error")
 	}
-	_, errDuplicateInsert := th.Insert(ctx, "member", id, s)
+	_, _, errDuplicateInsert := th.Insert(ctx, "member", id, s)
 	if errDuplicateInsert == nil {
 		t.Error("error missing", errDuplicateInsert)
 	}
@@ -107,7 +119,7 @@ func TestInsertExpectDuplicateError(t *testing.T) {
 
 func testInsert() (webshop, string, error) {
 	ws := generate()
-	id, err := th.Insert(context.Background(), "webshop", "", ws)
+	_, id, err := th.Insert(context.Background(), "webshop", "", ws)
 	return ws, id, err
 }
 
@@ -137,7 +149,7 @@ func TestGetNullString(t *testing.T) {
 		IssuingBank: "",
 		CardType:    null.String{String: "US", Valid: true},
 	}
-	id, err := th.Insert(context.Background(), "card_type", "", cardTypeWrite)
+	_, id, err := th.Insert(context.Background(), "card_type", "", cardTypeWrite)
 	if err != nil {
 		t.Error(err)
 	}
@@ -159,7 +171,7 @@ func TestGetPrimitivePtrNil(t *testing.T) {
 		Job *string `json:"name,omitempty"`
 	}
 	test := wtyp{Job: &a}
-	id, errInsert := th.Insert(context.Background(), "webshop", "", test)
+	_, id, errInsert := th.Insert(context.Background(), "webshop", "", test)
 	if errInsert != nil {
 		t.Error("Error")
 	}
@@ -177,7 +189,7 @@ func TestGetPrimitivePtr(t *testing.T) {
 		Job *string `json:"name,omitempty"`
 	}
 	test := wtyp{Job: &a}
-	id, errInsert := th.Insert(context.Background(), "webshop", "", test)
+	_, id, errInsert := th.Insert(context.Background(), "webshop", "", test)
 	if errInsert != nil {
 		t.Error("Error")
 	}
@@ -196,7 +208,7 @@ func TestGetNonPointerInput(t *testing.T) {
 		Job *string `json:"name,omitempty"`
 	}
 	test := wtyp{Job: &a}
-	id, errInsert := th.Insert(context.Background(), "webshop", "", test)
+	_, id, errInsert := th.Insert(context.Background(), "webshop", "", test)
 	if errInsert != nil {
 		t.Error("Error")
 	}
@@ -214,7 +226,7 @@ func TestGetNonExportedField(t *testing.T) {
 		job string
 	}
 	testInsert := wtyp{job: a}
-	id, errInsert := th.Insert(context.Background(), "webshop", "", testInsert)
+	_, id, errInsert := th.Insert(context.Background(), "webshop", "", testInsert)
 	if errInsert != nil {
 		t.Error("Error")
 	}
@@ -309,21 +321,25 @@ func TestUpsertSameID(t *testing.T) {
 
 func TestUpsertPtrValueNewID(t *testing.T) {
 	ws := generate()
-	id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), &ws, 0)
+	cas, id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), &ws, 0)
 	if err != nil || id == "" {
 		t.Fatal(err)
 	}
+	if len(cas) != 3 {
+		t.Errorf("Cas should store 3 element, instead of %d", len(cas))
+
+	}
 }
 
 func TestUpsertPtrValueSameID(t *testing.T) {
 	ws := generate()
 	id := xid.New().String()
-	_, err := th.Upsert(context.Background(), "webshop", id, &ws, 0)
+	_, _, err := th.Upsert(context.Background(), "webshop", id, &ws, 0)
 	if err != nil {
 		t.Fatal(err)
 	}
 	wsD := generate()
-	_, errD := th.Upsert(context.Background(), "webshop", id, &wsD, 1)
+	_, _, errD := th.Upsert(context.Background(), "webshop", id, &wsD, 1)
 	if errD != nil {
 		t.Fatal(errD)
 	}
@@ -339,30 +355,40 @@ func TestUpsertPrimitivePtr(t *testing.T) {
 	s := struct {
 		Name *string `json:"name,omitempty"`
 	}{Name: &asd}
-	id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
+	cas, id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+
+	}
 }
 
 func TestUpsertPrimitivePtrNil(t *testing.T) {
 	s := struct {
 		Name *string `json:"name,omitempty"`
 	}{}
-	id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
+	cas, id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+	}
 }
 
 func TestUpsertNonExportedField(t *testing.T) {
 	s := struct {
 		name string
 	}{name: "Jackson"}
-	id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
+	cas, id, err := th.Upsert(context.Background(), "webshop", xid.New().String(), s, 0)
 	if err != nil || id == "" {
 		t.Error("Missing error")
 	}
+	if len(cas) != 1 {
+		t.Errorf("Cas should store 1 element, instead of %d", len(cas))
+	}
 }
 
 func TestUpsertEmptyID(t *testing.T) {
@@ -377,7 +403,7 @@ func TestUpsertEmptyID(t *testing.T) {
 
 func testUpsert(id string) (webshop, string, error) {
 	ws := generate()
-	id, err := th.Upsert(context.Background(), "webshop", id, ws, 0)
+	_, id, err := th.Upsert(context.Background(), "webshop", id, ws, 0)
 	return ws, id, err
 }
 
@@ -402,14 +428,14 @@ func BenchmarkInsertEmb(b *testing.B) {
 
 func BenchmarkInsert(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		_, _ = th.Insert(context.Background(), "webshop", "", generate())
+		_, _, _ = th.Insert(context.Background(), "webshop", "", generate())
 	}
 }
 
 func BenchmarkGetSingle(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		startInsert := time.Now()
-		ID, _ := th.Insert(context.Background(), "webshop", "", generate())
+		_, ID, _ := th.Insert(context.Background(), "webshop", "", generate())
 		fmt.Printf("Insert: %vns\tGet: ", time.Since(startInsert).Nanoseconds())
 		start := time.Now()
 		_ = th.Get(context.Background(), "webshop", ID, webshop{})
@@ -436,7 +462,7 @@ func BenchmarkGetPtr(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		job := jobtyp{Job: &j}
 		startInsert := time.Now()
-		id, _ := th.Insert(context.Background(), "job", "", job)
+		_, id, _ := th.Insert(context.Background(), "job", "", job)
 		fmt.Printf("Insert: %vns\tGet: ", time.Since(startInsert).Nanoseconds())
 		var jobRead jobtyp
 		start := time.Now()