diff --git a/tiny_gltf.h b/tiny_gltf.h
index 7481345..5722ee1 100644
--- a/tiny_gltf.h
+++ b/tiny_gltf.h
@@ -27,6 +27,7 @@
 
 // Version:
 //  - v2.6.0 Disable expanding file path for security(no use of awkward `wordexp` anymore).
+//           Support serializing sparse accessor(Thanks to @fynv).
 //  - v2.5.0 Add SetPreserveImageChannels() option to load image data as is.
 //  - v2.4.3 Fix null object output when when material has all default
 //  parameters.
@@ -1434,6 +1435,10 @@ class TinyGLTF {
   bool preserve_image_channels_ = false;  /// Default false(expand channels to
                                           /// RGBA) for backward compatibility.
 
+  // Warning & error messages
+  std::string warn_;
+  std::string err_;
+
   FsCallbacks fs = {
 #ifndef TINYGLTF_NO_FS
       &tinygltf::FileExists, &tinygltf::ExpandFilePath,
@@ -6711,6 +6716,27 @@ static void SerializeGltfAccessor(Accessor &accessor, json &o) {
   if (accessor.extras.Type() != NULL_TYPE) {
     SerializeValue("extras", accessor.extras, o);
   }
+
+  // sparse
+  if (accessor.sparse.isSparse)
+  {
+      json sparse;
+      SerializeNumberProperty<int>("count", accessor.sparse.count, sparse);
+      {
+          json indices;
+          SerializeNumberProperty<int>("bufferView", accessor.sparse.indices.bufferView, indices);
+          SerializeNumberProperty<int>("byteOffset", accessor.sparse.indices.byteOffset, indices);
+          SerializeNumberProperty<int>("componentType", accessor.sparse.indices.componentType, indices);
+          JsonAddMember(sparse, "indices", std::move(indices));
+      }
+      {
+          json values;
+          SerializeNumberProperty<int>("bufferView", accessor.sparse.values.bufferView, values);
+          SerializeNumberProperty<int>("byteOffset", accessor.sparse.values.byteOffset, values);
+          JsonAddMember(sparse, "values", std::move(values));
+      }
+      JsonAddMember(o, "sparse", std::move(sparse));
+  }
 }
 
 static void SerializeGltfAnimationChannel(AnimationChannel &channel, json &o) {
@@ -7547,7 +7573,7 @@ static bool WriteGltfFile(const std::string &output,
   return WriteGltfStream(gltfFile, content);
 }
 
-static void WriteBinaryGltfStream(std::ostream &stream,
+static bool WriteBinaryGltfStream(std::ostream &stream,
                                   const std::string &content,
                                   const std::vector<unsigned char> &binBuffer) {
   const std::string header = "glTF";
@@ -7603,9 +7629,12 @@ static void WriteBinaryGltfStream(std::ostream &stream,
                    std::streamsize(padding.size()));
     }
   }
+
+  // TODO: Check error on stream.write
+  return true;
 }
 
-static void WriteBinaryGltfFile(const std::string &output,
+static bool WriteBinaryGltfFile(const std::string &output,
                                 const std::string &content,
                                 const std::vector<unsigned char> &binBuffer) {
 #ifdef _WIN32
@@ -7623,7 +7652,7 @@ static void WriteBinaryGltfFile(const std::string &output,
 #else
   std::ofstream gltfFile(output.c_str(), std::ios::binary);
 #endif
-  WriteBinaryGltfStream(gltfFile, content, binBuffer);
+  return WriteBinaryGltfStream(gltfFile, content, binBuffer);
 }
 
 bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
@@ -7671,12 +7700,11 @@ bool TinyGLTF::WriteGltfSceneToStream(Model *model, std::ostream &stream,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfStream(stream, JsonToString(output), binBuffer);
+    return WriteBinaryGltfStream(stream, JsonToString(output), binBuffer);
   } else {
-    WriteGltfStream(stream, JsonToString(output, prettyPrint ? 2 : -1));
+    return WriteGltfStream(stream, JsonToString(output, prettyPrint ? 2 : -1));
   }
 
-  return true;
 }
 
 bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
@@ -7761,12 +7789,11 @@ bool TinyGLTF::WriteGltfSceneToFile(Model *model, const std::string &filename,
   }
 
   if (writeBinary) {
-    WriteBinaryGltfFile(filename, JsonToString(output), binBuffer);
+    return WriteBinaryGltfFile(filename, JsonToString(output), binBuffer);
   } else {
-    WriteGltfFile(filename, JsonToString(output, (prettyPrint ? 2 : -1)));
+    return WriteGltfFile(filename, JsonToString(output, (prettyPrint ? 2 : -1)));
   }
 
-  return true;
 }
 
 }  // namespace tinygltf