openutau · atouu · Jun 7, 2026
diff --git a/OpenUtau.Core/DiffSinger/DiffSingerScript.cs b/OpenUtau.Core/DiffSinger/DiffSingerScript.cs
@@ -4,7 +4,6 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using Newtonsoft.Json;
 using OpenUtau.Core.Render;
 using OpenUtau.Core.Ustx;
 
@@ -199,7 +198,7 @@ static public void SavePart(UProject project, UVoicePart part, string filePath,
                 .Select(x => new DiffSingerScript(x, options).toRaw())
                 .ToArray();
             File.WriteAllText(filePath,
-                JsonConvert.SerializeObject(ScriptArray, Formatting.Indented),
+                Json.Serialize(ScriptArray),
                 new UTF8Encoding(false));
         }
     }

diff --git a/OpenUtau.Core/DiffSinger/DiffSingerUtils.cs b/OpenUtau.Core/DiffSinger/DiffSingerUtils.cs
@@ -4,7 +4,6 @@
 using System.Linq;
 using System.Text;
 using Microsoft.ML.OnnxRuntime.Tensors;
-using Newtonsoft.Json;
 using OpenUtau.Core.Render;
 
 namespace OpenUtau.Core.DiffSinger {
@@ -319,7 +318,7 @@ public static Dictionary<string, int> LoadPhonemes(string filePath){
 
         static Dictionary<string, int> LoadPhonemesFromJson(string filePath){
             var json = File.ReadAllText(filePath, Encoding.UTF8);
-            return JsonConvert.DeserializeObject<Dictionary<string, int>>(json);
+            return Json.Deserialize<Dictionary<string, int>>(json);
         }
 
         static Dictionary<string, int> LoadPhonemesFromTxt(string filePath){
@@ -333,7 +332,7 @@ static Dictionary<string, int> LoadPhonemesFromTxt(string filePath){
 
         public static Dictionary<string, int> LoadLanguageIds(string filePath){
             var json = File.ReadAllText(filePath, Encoding.UTF8);
-            return JsonConvert.DeserializeObject<Dictionary<string, int>>(json);
+            return Json.Deserialize<Dictionary<string, int>>(json);
         }
 
         public static string PhonemeLanguage(string phoneme){

diff --git a/OpenUtau.Core/Enunu/EnunuClient.cs b/OpenUtau.Core/Enunu/EnunuClient.cs
@@ -1,7 +1,6 @@
 using System;
 using NetMQ;
 using NetMQ.Sockets;
-using Newtonsoft.Json;
 using Serilog;
 
 namespace OpenUtau.Core.Enunu {
@@ -12,15 +11,15 @@ internal T SendRequest<T>(string[] args) {
         internal T SendRequest<T>(string[] args, string port,int second = 300 ) {
             using (var client = new RequestSocket()) {
                 client.Connect($"tcp://localhost:{port}");
-                string request = JsonConvert.SerializeObject(args);
+                string request = Json.Serialize(args);
                 Log.Information($"EnunuProcess sending {request}");
                 client.SendFrame(request);
                 client.TryReceiveFrameString(TimeSpan.FromSeconds(second), out string? message);
                 Log.Information($"EnunuProcess received {message}");
                 if (string.IsNullOrEmpty(message)) {
                     return (T)Activator.CreateInstance(typeof(T))!;
                 }
-                return JsonConvert.DeserializeObject<T>(message ?? string.Empty)!;
+                return Json.Deserialize<T>(message ?? string.Empty)!;
             }
         }
     }

diff --git a/OpenUtau.Core/Format/Commonnote.cs b/OpenUtau.Core/Format/Commonnote.cs
@@ -1,13 +1,8 @@
-using Melanchall.DryWetMidi.Core;
-using Melanchall.DryWetMidi.Interaction;
-using Newtonsoft.Json;
-using OpenUtau.Core.Ustx;
+using OpenUtau.Core.Ustx;
 using OpenUtau.Core.Util;
 using System;
 using System.Collections.Generic;
-using System.ComponentModel.Design;
 using System.Linq;
-using System.Reflection.Emit;
 using TextCopy;
 using Serilog;
 
@@ -62,11 +57,11 @@ public static string Dumps(List<UNote> uNotes, UProject project) {
                 },
                 notes = uNotes.Select(DumpNote).ToList(),
             };
-            return JsonConvert.SerializeObject(data);
+            return Json.Serialize(data);
         }
 
         public static List<UNote> Loads(string text, UProject project) {
-            var data = JsonConvert.DeserializeObject<CommonnoteData>(text);
+            var data = Json.Deserialize<CommonnoteData>(text);
             if (data.identifier != "commonnote") {
                 Log.Error($"Clipboard is missing commonnote header");
                 return null;

diff --git a/OpenUtau.Core/Format/Ufdata.cs b/OpenUtau.Core/Format/Ufdata.cs
@@ -1,8 +1,6 @@
 using System.IO;
 using System.Linq;
 using System.Text;
-using Newtonsoft.Json;
-
 using OpenUtau.Core.Ustx;
 
 //reference: https://github.com/sdercolin/utaformatix-data/blob/main/lib/csharp/UtaFormatix.Data
@@ -118,7 +116,7 @@ public static UProject Load(string file){
             Ustx.AddDefaultExpressions(project);
             project.FilePath = file;
 
-            var ufProject = JsonConvert.DeserializeObject<UfFile>(File.ReadAllText(file,Encoding.UTF8)).project;
+            var ufProject = Json.Deserialize<UfFile>(File.ReadAllText(file,Encoding.UTF8)).project;
 
             //parse tempo
             project.tempos=ufProject.tempos

diff --git a/OpenUtau.Core/OpenUtau.Core.csproj b/OpenUtau.Core/OpenUtau.Core.csproj
@@ -18,7 +18,6 @@
     <PackageReference Include="NAudio.Core" Version="2.2.1" />
     <PackageReference Include="NAudio.Vorbis" Version="1.5.0" />
     <PackageReference Include="NeoLua" Version="1.3.19" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="NLayer.NAudioSupport" Version="1.4.0" />
     <PackageReference Include="NumSharp" Version="0.30.0" />
     <PackageReference Include="NWaves" Version="0.9.6" />

diff --git a/OpenUtau.Core/PackageManager.cs b/OpenUtau.Core/PackageManager.cs
@@ -5,9 +5,9 @@
 using System.Net.Http;
 using System.Security.Cryptography;
 using System.Text;
+using System.Text.Json;
+using System.Text.Json.Nodes;
 using System.Threading.Tasks;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
 using Serilog;
 using SharpCompress.Archives;
 using OpenUtau.Core.Util;
@@ -63,10 +63,10 @@ public async Task<List<RegistrySoftware>> FetchRegistryAsync() {
 
             List<RegistrySoftware> list = new List<RegistrySoftware>();
             try {
-                var token = JToken.Parse(body);
-                var items = token["items"];
-                if (items != null && items.Type == JTokenType.Array) {
-                    list = items.ToObject<List<RegistrySoftware>>() ?? new List<RegistrySoftware>();
+                var token = JsonObject.Parse(body);
+                var items = token?["items"];
+                if (items?.GetValueKind() == JsonValueKind.Array) {
+                    list = Json.Deserialize<List<RegistrySoftware>>(items) ?? new List<RegistrySoftware>();
                 }
             } catch (Exception e) {
                 Log.Warning(e, "Failed to parse registry JSON");

diff --git a/OpenUtau.Core/Util/Json.cs b/OpenUtau.Core/Util/Json.cs
@@ -0,0 +1,32 @@
+using System.IO;
+using System.Text.Encodings.Web;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace OpenUtau.Core {
+    public class Json {
+
+        public static readonly JsonSerializerOptions DefaultJsonOptions = new() {
+            Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
+            IncludeFields = true,
+            WriteIndented = true
+        };
+
+        public static string Serialize(object? graph, JsonSerializerOptions? options = null) {
+            return JsonSerializer.Serialize(graph, options ?? DefaultJsonOptions);
+        }
+
+        public static T? Deserialize<T>(string input, JsonSerializerOptions? options = null) {
+            return JsonSerializer.Deserialize<T>(input, options ?? DefaultJsonOptions);
+        }
+
+        public static T? Deserialize<T>(Stream input, JsonSerializerOptions? options = null) {
+            return JsonSerializer.Deserialize<T>(input, options ?? DefaultJsonOptions);
+        }
+
+        public static T? Deserialize<T>(JsonNode? input, JsonSerializerOptions? options = null) {
+            return input.Deserialize<T>(options ?? DefaultJsonOptions);
+        }
+
+    }
+}
diff --git a/OpenUtau.Core/Util/NotePresets.cs b/OpenUtau.Core/Util/NotePresets.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
-using Newtonsoft.Json;
 using OpenUtau.Core.Ustx;
 using Serilog;
 
@@ -17,7 +16,7 @@ static NotePresets() {
         public static void Save() {
             try {
                 File.WriteAllText(PathManager.Inst.NotePresetsFilePath,
-                    JsonConvert.SerializeObject(Default, Formatting.Indented),
+                    Json.Serialize(Default),
                     Encoding.UTF8);
             } catch (Exception e) {
                 Log.Error(e, "Failed to save note presets.");
@@ -27,7 +26,7 @@ public static void Save() {
         private static void Load() {
             try {
                 if (File.Exists(PathManager.Inst.NotePresetsFilePath)) {
-                    Default = JsonConvert.DeserializeObject<SerializableNotePresets>(
+                    Default = Json.Deserialize<SerializableNotePresets>(
                         File.ReadAllText(PathManager.Inst.NotePresetsFilePath, Encoding.UTF8));
                 } else {
                     Reset();

diff --git a/OpenUtau.Core/Util/Preferences.cs b/OpenUtau.Core/Util/Preferences.cs
@@ -4,14 +4,14 @@
 using System.Globalization;
 using System.IO;
 using System.Text;
-using Newtonsoft.Json;
+using System.Text.Json.Serialization;
 using OpenUtau.Core.Render;
 using Serilog;
 
 namespace OpenUtau.Core.Util {
 
     public static class Preferences {
-        public static SerializablePreferences Default;
+        public static SerializablePreferences Default { get; private set; }
 
         static Preferences() {
             Load();
@@ -20,7 +20,7 @@ static Preferences() {
         public static void Save() {
             try {
                 File.WriteAllText(PathManager.Inst.PrefsFilePath,
-                    JsonConvert.SerializeObject(Default, Formatting.Indented),
+                    Json.Serialize(Default),
                     Encoding.UTF8);
             } catch (Exception e) {
                 Log.Error(e, "Failed to save prefs.");
@@ -34,7 +34,7 @@ public static void Reset() {
                 string exePath = Path.GetDirectoryName(Process.GetCurrentProcess().MainModule.FileName);
                 string shippedPrefsPath = Path.Combine(exePath, "prefs-default.json");
                 if (File.Exists(shippedPrefsPath)) {
-                    var shippedPrefs = JsonConvert.DeserializeObject<SerializablePreferences>(
+                    var shippedPrefs = Json.Deserialize<SerializablePreferences>(
                         File.ReadAllText(shippedPrefsPath, Encoding.UTF8));
                     if (shippedPrefs != null) {
                         Default = shippedPrefs;
@@ -102,7 +102,7 @@ private static void AddRecentFile(string filePath) {
         private static void Load() {
             try {
                 if (File.Exists(PathManager.Inst.PrefsFilePath)) {
-                    Default = JsonConvert.DeserializeObject<SerializablePreferences>(
+                    Default = Json.Deserialize<SerializablePreferences>(
                         File.ReadAllText(PathManager.Inst.PrefsFilePath, Encoding.UTF8));
                     if(Default == null) {
                         Reset();
@@ -217,43 +217,44 @@ public class SerializablePreferences {
             public bool LockUnselectedNotesVibrato = true;
             public bool LockUnselectedNotesExpressions = true;
             public bool VoicebankPublishUseIgnore = true;
-            public string VoicebankPublishIgnores = @"#Adobe Audition
-*.pkf
+            public string VoicebankPublishIgnores = """
+                #Adobe Audition
+                *.pkf
 
-#UTAU Engines
-*.ctspec
-*.d4c
-*.dio
-*.frc
-*.frt
-#*.frq
-*.harvest
-*.lessaudio
-*.llsm
-*.mrq
-*.pitchtier
-*.pkf
-*.platinum
-*.pmk
-*.sc.npz
-*.star
-*.uspec
-*.vs4ufrq
+                #UTAU Engines
+                *.ctspec
+                *.d4c
+                *.dio
+                *.frc
+                *.frt
+                #*.frq
+                *.harvest
+                *.lessaudio
+                *.llsm
+                *.mrq
+                *.pitchtier
+                *.pkf
+                *.platinum
+                *.pmk
+                *.sc.npz
+                *.star
+                *.uspec
+                *.vs4ufrq
 
-#UTAU related tools
-\$read
-*.setParam-Scache
-*.lbp
-*.lbp.caches/*
+                #UTAU related tools
+                \$read
+                *.setParam-Scache
+                *.lbp
+                *.lbp.caches/*
 
-#OpenUtau
-errors.txt
-";
+                #OpenUtau
+                errors.txt
+                """;
             public string RecoveryPath = string.Empty;
             public bool DetachPianoRoll = false;
 
             // Legacy
-            [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+            [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
             public int? Theme;
         }
     }

diff --git a/OpenUtau.Core/Vogen/VogenSingerLoader.cs b/OpenUtau.Core/Vogen/VogenSingerLoader.cs
@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Text;
-using Newtonsoft.Json;
 using OpenUtau.Core.Ustx;
 using OpenUtau.Core.Util;
 using Serilog;
@@ -76,9 +74,7 @@ public USinger LoadSinger(string filePath) {
                     throw new ArgumentException("missing meta.json");
                 }
                 using (var stream = metaEntry.OpenEntryStream()) {
-                    using var reader = new StreamReader(stream, Encoding.UTF8);
-                    JsonSerializer serializer = new JsonSerializer();
-                    meta = (VogenMeta)serializer.Deserialize(reader, typeof(VogenMeta));
+                    meta = Json.Deserialize<VogenMeta>(stream);
                 }
                 model = Zip.ExtractBytes(archive, "model.onnx");
                 if (model == null) {