Added JSON serialization details

Author: AndyButland

16/umbraco-cms/SUMMARY.md

@@ -420,6 +420,7 @@
 * [Umbraco Flavored Markdown](reference/umbraco-flavored-markdown.md)
 * [Content Type Filters](reference/content-type-filters.md)
 * [Database Availability Checks](reference/database-availability.md)
+* [JSON Serialization](reference/json-serialization.md)
 
 ## Tutorials
 

16/umbraco-cms/reference/json-serialization.md

@@ -0,0 +1,48 @@
+---
+description: Describes how the JSON serialization within Umbraco can be customized.
+---
+
+# JSON Serialization
+
+Umbraco uses JSON as a format to serialize information to the database and for output. For example, the configuration of data types and the property values of complex editors are serialized to JSON for persistence.
+
+The serializers within Umbraco uses a `JavascriptEncoder` which only considers basic latin characters as unnecessary to encode.
+
+## Implementing Custom Behavior
+
+For projects making use of non-Latin characters you may want to amend this behavior. By doing so you can reduce the space the serialized information takes up in the database.
+
+We support this by abstracting the default behavior behind the `IJsonSerializerEncoderFactory` interface found in the `Umbraco.Cms.Core.Serialization` namespace.
+
+You can implement your own version of this interface and register it via a composer. This is shown in the following example that marks Cyrillic characters as excluded for encoding:
+
+```csharp
+using System.Text.Encodings.Web;
+using System.Text.Unicode;
+using Umbraco.Cms.Core.Composing;
+using Umbraco.Cms.Core.Serialization;
+using Umbraco.Cms.Infrastructure.Serialization;
+
+namespace Umbraco.Cms.Web.UI.Custom.SystemTextConfigurationEditor;
+
+public class SystemTextConfigurationEditorComposer : IComposer
+{
+    public void Compose(IUmbracoBuilder builder)
+    {
+        builder.Services.AddUnique<IJsonSerializerEncoderFactory, MyConfigurationEditorJsonSerializerEncoderFactory>();
+    }
+}
+
+internal class MyConfigurationEditorJsonSerializerEncoderFactory : IJsonSerializerEncoderFactory
+{
+    public JavaScriptEncoder CreateEncoder<TSerializer>()
+        where TSerializer : IJsonSerializer
+    {
+        return JavaScriptEncoder.Create(UnicodeRanges.BasicLatin, UnicodeRanges.Cyrillic);
+    }
+}
+```
+
+For reference, the default implementation can be found [in the Umbraco CMS source code](https://github.com/umbraco/Umbraco-CMS/blob/main/src/Umbraco.Infrastructure/Serialization/DefaultJsonSerializerEncoderFactory.cs).
+
+