diff --git a/accounting/grpc/service_frostfs.pb.go b/accounting/grpc/service_frostfs.pb.go
index 4f11303..9c8c946 100644
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diff --git a/accounting/grpc/types_frostfs.pb.go b/accounting/grpc/types_frostfs.pb.go
index 8585583..b7e6b40 100644
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diff --git a/acl/grpc/types_frostfs.pb.go b/acl/grpc/types_frostfs.pb.go
index 1ba6c53..e5a6f32 100644
Binary files a/acl/grpc/types_frostfs.pb.go and b/acl/grpc/types_frostfs.pb.go differ
diff --git a/ape/grpc/types_frostfs.pb.go b/ape/grpc/types_frostfs.pb.go
index 7967e13..cf9499f 100644
Binary files a/ape/grpc/types_frostfs.pb.go and b/ape/grpc/types_frostfs.pb.go differ
diff --git a/apemanager/grpc/service_frostfs.pb.go b/apemanager/grpc/service_frostfs.pb.go
index 2a30850..7f3ed10 100644
Binary files a/apemanager/grpc/service_frostfs.pb.go and b/apemanager/grpc/service_frostfs.pb.go differ
diff --git a/container/grpc/service_frostfs.pb.go b/container/grpc/service_frostfs.pb.go
index 4ccb595..cc05dde 100644
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diff --git a/container/grpc/types_frostfs.pb.go b/container/grpc/types_frostfs.pb.go
index e5da35f..4ca23fa 100644
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diff --git a/lock/grpc/types_frostfs.pb.go b/lock/grpc/types_frostfs.pb.go
index 33f22c5..004a01f 100644
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diff --git a/netmap/grpc/service_frostfs.pb.go b/netmap/grpc/service_frostfs.pb.go
index 4d53031..9ebbf98 100644
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diff --git a/netmap/grpc/types_frostfs.pb.go b/netmap/grpc/types_frostfs.pb.go
index a4b10f9..0328531 100644
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diff --git a/object/grpc/service_frostfs.pb.go b/object/grpc/service_frostfs.pb.go
index f934f3b..9ee5a3d 100644
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diff --git a/object/grpc/types_frostfs.pb.go b/object/grpc/types_frostfs.pb.go
index 0ee939a..e4a916f 100644
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diff --git a/refs/grpc/types_frostfs.pb.go b/refs/grpc/types_frostfs.pb.go
index 3ed647c..5a16f8e 100644
Binary files a/refs/grpc/types_frostfs.pb.go and b/refs/grpc/types_frostfs.pb.go differ
diff --git a/session/grpc/service_frostfs.pb.go b/session/grpc/service_frostfs.pb.go
index c71325a..6d3ea9f 100644
Binary files a/session/grpc/service_frostfs.pb.go and b/session/grpc/service_frostfs.pb.go differ
diff --git a/session/grpc/types_frostfs.pb.go b/session/grpc/types_frostfs.pb.go
index e18c1ab..e9f3b42 100644
Binary files a/session/grpc/types_frostfs.pb.go and b/session/grpc/types_frostfs.pb.go differ
diff --git a/status/grpc/types_frostfs.pb.go b/status/grpc/types_frostfs.pb.go
index 609fc03..1d8b477 100644
Binary files a/status/grpc/types_frostfs.pb.go and b/status/grpc/types_frostfs.pb.go differ
diff --git a/tombstone/grpc/types_frostfs.pb.go b/tombstone/grpc/types_frostfs.pb.go
index e5b67d5..acb1836 100644
Binary files a/tombstone/grpc/types_frostfs.pb.go and b/tombstone/grpc/types_frostfs.pb.go differ
diff --git a/util/proto/marshal_test.go b/util/proto/marshal_test.go
index 8b717be..5498cf9 100644
--- a/util/proto/marshal_test.go
+++ b/util/proto/marshal_test.go
@@ -26,11 +26,37 @@ func nonZero[T protoInt]() T {
 
 func TestStableMarshalSingle(t *testing.T) {
 	t.Run("empty", func(t *testing.T) {
-		input := &generated.Primitives{}
-		require.Zero(t, input.StableSize())
+		t.Run("proto", func(t *testing.T) {
+			input := &generated.Primitives{}
+			require.Zero(t, input.StableSize())
 
-		r := input.MarshalProtobuf(nil)
-		require.Empty(t, r)
+			r := input.MarshalProtobuf(nil)
+			require.Empty(t, r)
+		})
+		t.Run("json", func(t *testing.T) {
+			input := &generated.Primitives{}
+			r, err := input.MarshalJSON()
+			require.NoError(t, err)
+			require.NotEmpty(t, r)
+
+			var actual test.Primitives
+			require.NoError(t, protojson.Unmarshal(r, &actual))
+
+			t.Run("protojson compatibility", func(t *testing.T) {
+				data, err := protojson.MarshalOptions{EmitUnpopulated: true}.Marshal(&actual)
+				require.NoError(t, err)
+				require.JSONEq(t, string(data), string(r))
+			})
+
+			var actualFrostfs generated.Primitives
+			require.NoError(t, actualFrostfs.UnmarshalJSON(r))
+			if len(actualFrostfs.FieldA) == 0 {
+				actualFrostfs.FieldA = nil
+			}
+			require.Equal(t, input, &actualFrostfs)
+
+			primitivesEqual(t, input, &actual)
+		})
 	})
 
 	marshalCases := []struct {
@@ -77,13 +103,16 @@ func TestStableMarshalSingle(t *testing.T) {
 				require.NoError(t, protojson.Unmarshal(r, &actual))
 
 				t.Run("protojson compatibility", func(t *testing.T) {
-					data, err := protojson.Marshal(&actual)
+					data, err := protojson.MarshalOptions{EmitUnpopulated: true}.Marshal(&actual)
 					require.NoError(t, err)
 					require.JSONEq(t, string(data), string(r))
 				})
 
 				var actualFrostfs generated.Primitives
 				require.NoError(t, actualFrostfs.UnmarshalJSON(r))
+				if len(actualFrostfs.FieldA) == 0 {
+					actualFrostfs.FieldA = nil
+				}
 				require.Equal(t, tc.input, &actualFrostfs)
 
 				primitivesEqual(t, tc.input, &actual)
@@ -94,7 +123,10 @@ func TestStableMarshalSingle(t *testing.T) {
 
 func primitivesEqual(t *testing.T, a *generated.Primitives, b *test.Primitives) {
 	// Compare each field directly, because proto-generated code has private fields.
-	require.Equal(t, a.FieldA, b.FieldA)
+	require.Equal(t, len(a.FieldA), len(b.FieldA))
+	if len(a.FieldA) != 0 {
+		require.Equal(t, a.FieldA, b.FieldA)
+	}
 	require.Equal(t, a.FieldB, b.FieldB)
 	require.Equal(t, a.FieldC, b.FieldC)
 	require.Equal(t, a.FieldD, b.FieldD)
diff --git a/util/proto/test/custom/test_frostfs.pb.go b/util/proto/test/custom/test_frostfs.pb.go
index 3804e46..f979038 100644
Binary files a/util/proto/test/custom/test_frostfs.pb.go and b/util/proto/test/custom/test_frostfs.pb.go differ
diff --git a/util/protogen/internalgengo/json.go b/util/protogen/internalgengo/json.go
index 3267955..15facfd 100644
--- a/util/protogen/internalgengo/json.go
+++ b/util/protogen/internalgengo/json.go
@@ -192,14 +192,17 @@ func emitJSONFieldWrite(g *protogen.GeneratedFile, f *protogen.Field, name strin
 
 	selector := name + "." + f.GoName
 
-	isNotDefault := notNil
-	if f.Desc.IsList() {
-		isNotDefault = notEmpty
-	} else if f.Desc.Kind() != protoreflect.MessageKind {
-		_, isNotDefault = easyprotoKindInfo(f.Desc.Kind())
-	}
-	g.P("if ", isNotDefault(selector), "{")
-	defer g.P("}")
+	// This code is responsible for ignoring default values.
+	// We will restore it after having parametrized JSON marshaling.
+	//
+	// isNotDefault := notNil
+	// if f.Desc.IsList() {
+	// 	isNotDefault = notEmpty
+	// } else if f.Desc.Kind() != protoreflect.MessageKind {
+	// 	_, isNotDefault = easyprotoKindInfo(f.Desc.Kind())
+	// }
+	// g.P("if ", isNotDefault(selector), "{")
+	// defer g.P("}")
 
 	g.P("if !first { out.RawByte(','); } else { first = false; }")
 	g.P("const prefix string = ", `"\"`, fieldJSONName(f), `\":"`)
@@ -247,7 +250,10 @@ func emitJSONFieldWrite(g *protogen.GeneratedFile, f *protogen.Field, name strin
 	case protoreflect.StringKind:
 		template = "out.String(%s)"
 	case protoreflect.BytesKind:
-		template = "out.Base64Bytes(%s)"
+		g.P("if ", selector, "!= nil {")
+		g.P("out.Base64Bytes(", selector, ")")
+		g.P("} else { out.String(\"\") }")
+		return
 	case protoreflect.MessageKind:
 		template = "%s.MarshalEasyJSON(out)"
 	case protoreflect.GroupKind: