diff --git a/src/Ramstack.HtmxToolkit/Internal/JsonOptions.cs b/src/Ramstack.HtmxToolkit/Internal/JsonOptions.cs
index 676f597..4b8e29f 100644
--- a/src/Ramstack.HtmxToolkit/Internal/JsonOptions.cs
+++ b/src/Ramstack.HtmxToolkit/Internal/JsonOptions.cs
@@ -1,5 +1,7 @@
+using System.Text.Encodings.Web;
 using System.Text.Json;
 using System.Text.Json.Serialization;
+using System.Text.Unicode;
 
 namespace Ramstack.HtmxToolkit.Internal;
 
@@ -8,6 +10,19 @@ namespace Ramstack.HtmxToolkit.Internal;
 /// </summary>
 internal static class JsonOptions
 {
+    /// <summary>
+    /// Encodes all Unicode ranges while escaping JavaScript and HTML-sensitive characters.
+    /// </summary>
+    private static readonly JavaScriptEncoder s_encoder =
+        JavaScriptEncoder.Create(new TextEncoderSettings(UnicodeRanges.All));
+
+    /// <summary>
+    /// Configures serializer options to preserve Unicode characters while escaping HTML-sensitive characters.
+    /// </summary>
+    /// <param name="options">The serializer options to configure.</param>
+    public static void ConfigureHtmlSafeUnicode(JsonSerializerOptions options) =>
+        options.Encoder = s_encoder;
+
     /// <summary>
     /// JSON serializer options using <see cref="JsonNamingPolicy.CamelCase"/> for property names and dictionary keys,
     /// and ignoring properties with <see langword="null"/> values.
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigJsonSerializerContext.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigJsonSerializerContext.cs
index d02b71a..95ecb92 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigJsonSerializerContext.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigJsonSerializerContext.cs
@@ -1,11 +1,26 @@
 using System.Text.Json.Serialization;
 
+using Ramstack.HtmxToolkit.Internal;
+
 namespace Ramstack.HtmxToolkit.TagHelpers;
 
+/// <summary>
+/// Provides source-generated JSON serialization metadata for HTMX configuration data.
+/// </summary>
 [JsonSourceGenerationOptions(
     WriteIndented = false,
     PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
     DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
-    GenerationMode = JsonSourceGenerationMode.Serialization)]
+    GenerationMode = JsonSourceGenerationMode.Default)]
 [JsonSerializable(typeof(HtmxConfigTagHelper.HtmxConfigData))]
-internal partial class HtmxConfigJsonSerializerContext : JsonSerializerContext;
+internal partial class HtmxConfigJsonSerializerContext : JsonSerializerContext
+{
+    /// <summary>
+    /// Initializes the default serializer context with HTML-safe Unicode encoding.
+    /// </summary>
+    static HtmxConfigJsonSerializerContext()
+    {
+        JsonOptions.ConfigureHtmlSafeUnicode(s_defaultOptions);
+        s_defaultContext = new HtmxConfigJsonSerializerContext(s_defaultOptions);
+    }
+}
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigTagHelper.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigTagHelper.cs
index db3ef07..d6e45b7 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigTagHelper.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxConfigTagHelper.cs
@@ -516,10 +516,8 @@ public override async Task ProcessAsync(TagHelperContext context, TagHelperOutpu
         if (IncludeAntiForgeryToken)
             _config.AntiForgery = antiforgery.GetAndStoreTokens(ViewContext.HttpContext);
 
-        var config = new HtmlString(
-            JsonSerializer.Serialize(
-                _config,
-                HtmxConfigJsonSerializerContext.Default.HtmxConfigData));
+        var info = HtmxConfigJsonSerializerContext.Default.HtmxConfigData;
+        var config = new HtmlString(JsonSerializer.Serialize(_config, info));
 
         output.Attributes.SetAttribute(
             new TagHelperAttribute("content", config, HtmlAttributeValueStyle.SingleQuotes));
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxDictionaryJsonSerializerContext.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxDictionaryJsonSerializerContext.cs
index ae4ce45..5aea042 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxDictionaryJsonSerializerContext.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxDictionaryJsonSerializerContext.cs
@@ -1,7 +1,22 @@
 using System.Text.Json.Serialization;
 
+using Ramstack.HtmxToolkit.Internal;
+
 namespace Ramstack.HtmxToolkit.TagHelpers;
 
+/// <summary>
+/// Provides source-generated JSON serialization metadata for HTMX string dictionaries.
+/// </summary>
 [JsonSerializable(typeof(IDictionary<string, string>))]
-[JsonSourceGenerationOptions(WriteIndented = false, GenerationMode = JsonSourceGenerationMode.Serialization)]
-internal partial class HtmxDictionaryJsonSerializerContext : JsonSerializerContext;
+[JsonSourceGenerationOptions(WriteIndented = false, GenerationMode = JsonSourceGenerationMode.Default)]
+internal partial class HtmxDictionaryJsonSerializerContext : JsonSerializerContext
+{
+    /// <summary>
+    /// Initializes the default serializer context with HTML-safe Unicode encoding.
+    /// </summary>
+    static HtmxDictionaryJsonSerializerContext()
+    {
+        JsonOptions.ConfigureHtmlSafeUnicode(s_defaultOptions);
+        s_defaultContext = new HtmxDictionaryJsonSerializerContext(s_defaultOptions);
+    }
+}
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxHeaderTagHelper.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxHeaderTagHelper.cs
index 9204d43..d69f0fc 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxHeaderTagHelper.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxHeaderTagHelper.cs
@@ -42,8 +42,7 @@ public override Task ProcessAsync(TagHelperContext context, TagHelperOutput outp
             var headers = new HtmlString(JsonSerializer.Serialize(Headers, info));
 
             output.Attributes.SetAttribute(
-                new TagHelperAttribute("hx-headers", headers, HtmlAttributeValueStyle.SingleQuotes)
-                );
+                new TagHelperAttribute("hx-headers", headers, HtmlAttributeValueStyle.SingleQuotes));
         }
 
         return Task.CompletedTask;
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestJsonSerializerContext.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestJsonSerializerContext.cs
index 9db20e7..7bfdeac 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestJsonSerializerContext.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestJsonSerializerContext.cs
@@ -1,11 +1,26 @@
 using System.Text.Json.Serialization;
 
+using Ramstack.HtmxToolkit.Internal;
+
 namespace Ramstack.HtmxToolkit.TagHelpers;
 
+/// <summary>
+/// Provides source-generated JSON serialization metadata for HTMX request configuration data.
+/// </summary>
 [JsonSourceGenerationOptions(
     WriteIndented = false,
     PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
     DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
-    GenerationMode = JsonSourceGenerationMode.Serialization)]
+    GenerationMode = JsonSourceGenerationMode.Default)]
 [JsonSerializable(typeof(HtmxRequestTagHelper.HtmxRequestData))]
-internal partial class HtmxRequestJsonSerializerContext : JsonSerializerContext;
+internal partial class HtmxRequestJsonSerializerContext : JsonSerializerContext
+{
+    /// <summary>
+    /// Initializes the default serializer context with HTML-safe Unicode encoding.
+    /// </summary>
+    static HtmxRequestJsonSerializerContext()
+    {
+        JsonOptions.ConfigureHtmlSafeUnicode(s_defaultOptions);
+        s_defaultContext = new HtmxRequestJsonSerializerContext(s_defaultOptions);
+    }
+}
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestTagHelper.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestTagHelper.cs
index bb2b429..749afed 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestTagHelper.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxRequestTagHelper.cs
@@ -60,11 +60,9 @@ public override Task ProcessAsync(TagHelperContext context, TagHelperOutput outp
     {
         if (Timeout is not null || Credentials is not null || NoHeaders is not null)
         {
-            var request = new HtmlString(
-                JsonSerializer.Serialize(_request, HtmxRequestJsonSerializerContext.Default.HtmxRequestData));
-
-            output.Attributes.SetAttribute(
-                new TagHelperAttribute("hx-request", request, HtmlAttributeValueStyle.SingleQuotes));
+            var info = HtmxRequestJsonSerializerContext.Default.HtmxRequestData;
+            var request = new HtmlString(JsonSerializer.Serialize(_request, info));
+            output.Attributes.SetAttribute(new TagHelperAttribute("hx-request", request));
         }
 
         return Task.CompletedTask;
diff --git a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxValsTagHelper.cs b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxValsTagHelper.cs
index 6a4503a..ddc87fd 100644
--- a/src/Ramstack.HtmxToolkit/TagHelpers/HtmxValsTagHelper.cs
+++ b/src/Ramstack.HtmxToolkit/TagHelpers/HtmxValsTagHelper.cs
@@ -38,7 +38,8 @@ public override Task ProcessAsync(TagHelperContext context, TagHelperOutput outp
     {
         if (Values is { Count: > 0 } values)
         {
-            var json = JsonSerializer.Serialize(values, HtmxDictionaryJsonSerializerContext.Default.IDictionaryStringString);
+            var info = HtmxDictionaryJsonSerializerContext.Default.IDictionaryStringString;
+            var json = JsonSerializer.Serialize(values, info);
             var attribute = new TagHelperAttribute("hx-vals", new HtmlString(json), HtmlAttributeValueStyle.SingleQuotes);
 
             output.Attributes.SetAttribute(attribute);
diff --git a/tests/Ramstack.HtmxToolkit.Tests/HtmxConfigTagHelperTests.cs b/tests/Ramstack.HtmxToolkit.Tests/HtmxConfigTagHelperTests.cs
index 0d73752..372195d 100644
--- a/tests/Ramstack.HtmxToolkit.Tests/HtmxConfigTagHelperTests.cs
+++ b/tests/Ramstack.HtmxToolkit.Tests/HtmxConfigTagHelperTests.cs
@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Antiforgery;
+using Microsoft.AspNetCore.Html;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -60,7 +61,7 @@ public async Task ProcessAsync_SerializesConfiguredOptions()
             DefaultSwapDelay = 250,
             DefaultSettleDelay = 300,
             IncludeIndicatorStyles = false,
-            IndicatorClass = "my-indicator",
+            IndicatorClass = "индикатор's",
             RequestClass = "my-request",
             AddedClass = "my-added",
             SwappingClass = "my-swapping",
@@ -94,7 +95,13 @@ public async Task ProcessAsync_SerializesConfiguredOptions()
         var output = TestHelper.CreateTagHelperOutput();
         await helper.ProcessAsync(TestHelper.CreateTagHelperContext(), output);
 
-        var json = JsonHelper.ParseJson(GetContent(output));
+        Assert.That(output.Attributes["content"]!.Value, Is.TypeOf<HtmlString>());
+
+        var content = GetContent(output);
+        Assert.That(content, Does.Contain("\"индикатор\\u0027s\""));
+        Assert.That(content, Does.Not.Contain("'"));
+
+        var json = JsonHelper.ParseJson(content);
 
         Assert.That(json["historyEnabled"].GetBoolean(), Is.False);
         Assert.That(json["historyCacheSize"].GetInt32(), Is.EqualTo(42));
@@ -103,7 +110,7 @@ public async Task ProcessAsync_SerializesConfiguredOptions()
         Assert.That(json["defaultSwapDelay"].GetInt32(), Is.EqualTo(250));
         Assert.That(json["defaultSettleDelay"].GetInt32(), Is.EqualTo(300));
         Assert.That(json["includeIndicatorStyles"].GetBoolean(), Is.False);
-        Assert.That(json["indicatorClass"].GetString(), Is.EqualTo("my-indicator"));
+        Assert.That(json["indicatorClass"].GetString(), Is.EqualTo("индикатор's"));
         Assert.That(json["requestClass"].GetString(), Is.EqualTo("my-request"));
         Assert.That(json["addedClass"].GetString(), Is.EqualTo("my-added"));
         Assert.That(json["swappingClass"].GetString(), Is.EqualTo("my-swapping"));
diff --git a/tests/Ramstack.HtmxToolkit.Tests/HtmxHeaderTagHelperTests.cs b/tests/Ramstack.HtmxToolkit.Tests/HtmxHeaderTagHelperTests.cs
index 70956a2..3186c9f 100644
--- a/tests/Ramstack.HtmxToolkit.Tests/HtmxHeaderTagHelperTests.cs
+++ b/tests/Ramstack.HtmxToolkit.Tests/HtmxHeaderTagHelperTests.cs
@@ -1,3 +1,5 @@
+using Microsoft.AspNetCore.Html;
+
 namespace Ramstack.HtmxToolkit.Tests;
 
 [TestFixture]
@@ -7,26 +9,38 @@ public class HtmxHeaderTagHelperTests
     public async Task ProcessAsync_SerializesHeaders()
     {
         var output = TestHelper.CreateTagHelperOutput();
-        var helper = new HtmxHeaderTagHelper();
-        helper.Headers["X-Requested-With"] = "XMLHttpRequest";
-        helper.Headers["X-Custom"] = "value";
+        var helper = new HtmxHeaderTagHelper
+        {
+            Headers =
+            {
+                ["X-Requested-With"] = "XMLHttpRequest",
+                ["X-Custom"] = "value's"
+            }
+        };
 
         await helper.ProcessAsync(TestHelper.CreateTagHelperContext(), output);
         var attribute = output.Attributes["hx-headers"];
 
         Assert.That(attribute, Is.Not.Null);
+        Assert.That(attribute!.Value, Is.TypeOf<HtmlString>());
+        Assert.That(attribute.Value.ToString(), Is.EqualTo("{\"X-Requested-With\":\"XMLHttpRequest\",\"X-Custom\":\"value\\u0027s\"}"));
 
-        var json = JsonHelper.ParseJson(attribute!.Value.ToString()!);
+        var json = JsonHelper.ParseJson(attribute.Value.ToString()!);
         Assert.That(json["X-Requested-With"].GetString(), Is.EqualTo("XMLHttpRequest"));
-        Assert.That(json["X-Custom"].GetString(), Is.EqualTo("value"));
+        Assert.That(json["X-Custom"].GetString(), Is.EqualTo("value's"));
     }
 
     [Test]
     public void Headers_TreatsNamesAsCaseInsensitive()
     {
-        var helper = new HtmxHeaderTagHelper();
-        helper.Headers["X-Custom"] = "first";
-        helper.Headers["x-custom"] = "second";
+        var helper = new HtmxHeaderTagHelper
+        {
+            Headers =
+            {
+                ["X-Custom"] = "first",
+                ["x-custom"] = "second"
+            }
+        };
 
         Assert.That(helper.Headers, Has.Count.EqualTo(1));
         Assert.That(helper.Headers["X-CUSTOM"], Is.EqualTo("second"));
diff --git a/tests/Ramstack.HtmxToolkit.Tests/HtmxRequestTagHelperTests.cs b/tests/Ramstack.HtmxToolkit.Tests/HtmxRequestTagHelperTests.cs
index c66726b..d3a2692 100644
--- a/tests/Ramstack.HtmxToolkit.Tests/HtmxRequestTagHelperTests.cs
+++ b/tests/Ramstack.HtmxToolkit.Tests/HtmxRequestTagHelperTests.cs
@@ -1,3 +1,5 @@
+using Microsoft.AspNetCore.Html;
+
 namespace Ramstack.HtmxToolkit.Tests;
 
 [TestFixture]
@@ -18,8 +20,9 @@ public async Task ProcessAsync_SerializesRequestConfiguration()
         var attribute = output.Attributes["hx-request"];
 
         Assert.That(attribute, Is.Not.Null);
+        Assert.That(attribute!.Value, Is.TypeOf<HtmlString>());
 
-        var json = JsonHelper.ParseJson(attribute!.Value.ToString()!);
+        var json = JsonHelper.ParseJson(attribute.Value.ToString()!);
         Assert.That(json["timeout"].GetInt32(), Is.EqualTo(500));
         Assert.That(json["credentials"].GetBoolean(), Is.True);
         Assert.That(json["noHeaders"].GetBoolean(), Is.False);
diff --git a/tests/Ramstack.HtmxToolkit.Tests/HtmxValsTagHelperTests.cs b/tests/Ramstack.HtmxToolkit.Tests/HtmxValsTagHelperTests.cs
index 33c27a9..871ad1b 100644
--- a/tests/Ramstack.HtmxToolkit.Tests/HtmxValsTagHelperTests.cs
+++ b/tests/Ramstack.HtmxToolkit.Tests/HtmxValsTagHelperTests.cs
@@ -1,3 +1,5 @@
+using Microsoft.AspNetCore.Html;
+
 namespace Ramstack.HtmxToolkit.Tests;
 
 [TestFixture]
@@ -7,17 +9,31 @@ public class HtmxValsTagHelperTests
     public async Task ProcessAsync_SerializesValues()
     {
         var output = TestHelper.CreateTagHelperOutput();
-        var helper = new HtmxValsTagHelper();
-        helper.Values["category"] = "books";
-        helper.Values["sort"] = "title";
+        var helper = new HtmxValsTagHelper
+        {
+            Values =
+            {
+                ["категория"] = "Детские книги '<script>\" &",
+                ["sort"] = "title"
+            }
+        };
 
         await helper.ProcessAsync(TestHelper.CreateTagHelperContext(), output);
         var attribute = output.Attributes["hx-vals"];
 
         Assert.That(attribute, Is.Not.Null);
+        Assert.That(attribute!.Value, Is.TypeOf<HtmlString>());
+
+        var serialized = attribute.Value.ToString()!;
+
+        Assert.That(serialized, Is.EqualTo("{\"категория\":\"Детские книги \\u0027\\u003Cscript\\u003E\\u0022 \\u0026\",\"sort\":\"title\"}"));
+        Assert.That(serialized, Does.Not.Contain("'"));
+        Assert.That(serialized, Does.Not.Contain("<"));
+        Assert.That(serialized, Does.Not.Contain(">"));
+        Assert.That(serialized, Does.Not.Contain("&"));
 
-        var json = JsonHelper.ParseJson(attribute!.Value.ToString()!);
-        Assert.That(json["category"].GetString(), Is.EqualTo("books"));
+        var json = JsonHelper.ParseJson(serialized);
+        Assert.That(json["категория"].GetString(), Is.EqualTo("Детские книги '<script>\" &"));
         Assert.That(json["sort"].GetString(), Is.EqualTo("title"));
     }