diff --git a/third_party/dotnet/devtools/src/generator/BUILD.bazel b/third_party/dotnet/devtools/src/generator/BUILD.bazel
index c78f7516763d4..f202cd9df6387 100644
--- a/third_party/dotnet/devtools/src/generator/BUILD.bazel
+++ b/third_party/dotnet/devtools/src/generator/BUILD.bazel
@@ -3,8 +3,9 @@ load("//dotnet:defs.bzl", "csharp_binary", "framework")
 csharp_binary(
     name = "generator",
     srcs = glob(["**/*.cs"]),
+    nullable = "annotations",
     # Used as a tool in our build, so just target one framework
-    target_frameworks = ["net7.0"],
+    target_frameworks = ["net8.0"],
     visibility = [
         "//dotnet:__subpackages__",
     ],
@@ -14,6 +15,5 @@ csharp_binary(
         framework("nuget", "Humanizer.Core"),
         framework("nuget", "Microsoft.Extensions.DependencyInjection"),
         framework("nuget", "Microsoft.Extensions.DependencyInjection.Abstractions"),
-        framework("nuget", "Newtonsoft.Json"),
     ],
 )
diff --git a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationDefinitionTemplateSettings.cs b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationDefinitionTemplateSettings.cs
index c1758190172f8..2ff1ea9a9dcfa 100644
--- a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationDefinitionTemplateSettings.cs
+++ b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationDefinitionTemplateSettings.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.CodeGen
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
 
     /// <summary>
     /// Represents settings around Definition templates.
@@ -47,22 +47,22 @@ public CodeGenerationDefinitionTemplateSettings()
             };
         }
 
-        [JsonProperty("domainTemplate")]
+        [JsonPropertyName("domainTemplate")]
         public CodeGenerationTemplateSettings DomainTemplate { get; set; }
 
-        [JsonProperty("commandTemplate")]
+        [JsonPropertyName("commandTemplate")]
         public CodeGenerationTemplateSettings CommandTemplate { get; set; }
 
-        [JsonProperty("eventTemplate")]
+        [JsonPropertyName("eventTemplate")]
         public CodeGenerationTemplateSettings EventTemplate { get; set; }
 
-        [JsonProperty("typeObjectTemplate")]
+        [JsonPropertyName("typeObjectTemplate")]
         public CodeGenerationTemplateSettings TypeObjectTemplate { get; set; }
 
-        [JsonProperty("typeHashTemplate")]
+        [JsonPropertyName("typeHashTemplate")]
         public CodeGenerationTemplateSettings TypeHashTemplate { get; set; }
 
-        [JsonProperty("typeEnumTemplate")]
+        [JsonPropertyName("typeEnumTemplate")]
         public CodeGenerationTemplateSettings TypeEnumTemplate { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationSettings.cs b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationSettings.cs
index ebbf2c753107d..fdcd62b441d6a 100644
--- a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationSettings.cs
+++ b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationSettings.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.CodeGen
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System.Collections.Generic;
 
     /// <summary>
@@ -26,43 +26,43 @@ public CodeGenerationSettings()
         /// <summary>
         /// Collection of templates that will be parsed and output in the target folder.
         /// </summary>
-        [JsonProperty("include")]
+        [JsonPropertyName("include")]
         public ICollection<CodeGenerationTemplateSettings> Include { get; set; }
 
         /// <summary>
         /// Indicates whether or not domains marked as depreciated will be generated. (Default: true)
         /// </summary>
-        [JsonProperty("includeDeprecatedDomains")]
+        [JsonPropertyName("includeDeprecatedDomains")]
         public bool IncludeDeprecatedDomains { get; set; }
 
         /// <summary>
         /// Indicates whether or not domains marked as depreciated will be generated. (Default: true)
         /// </summary>
-        [JsonProperty("includeExperimentalDomains")]
+        [JsonPropertyName("includeExperimentalDomains")]
         public bool IncludeExperimentalDomains { get; set; }
 
         /// <summary>
         /// Gets or sets the root namespace of generated classes.
         /// </summary>
-        [JsonProperty("rootNamespace")]
+        [JsonPropertyName("rootNamespace")]
         public string RootNamespace { get; set; }
 
         /// <summary>
         /// Gets the version number of the runtime.
         /// </summary>
-        [JsonProperty("runtimeVersion")]
+        [JsonPropertyName("runtimeVersion")]
         public string RuntimeVersion { get; set; }
 
-        [JsonProperty("definitionTemplates")]
+        [JsonPropertyName("definitionTemplates")]
         public CodeGenerationDefinitionTemplateSettings DefinitionTemplates { get; set; }
 
-        [JsonProperty("templatesPath")]
+        [JsonPropertyName("templatesPath")]
         public string TemplatesPath { get; set; }
 
         /// <summary>
         /// The using statements that will be included on each generated file.
         /// </summary>
-        [JsonProperty("usingStatements")]
+        [JsonPropertyName("usingStatements")]
         public ICollection<string> UsingStatements { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationTemplateSettings.cs b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationTemplateSettings.cs
index 4f2dbe266a585..a5360955d5764 100644
--- a/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationTemplateSettings.cs
+++ b/third_party/dotnet/devtools/src/generator/CodeGen/CodeGenerationTemplateSettings.cs
@@ -1,16 +1,16 @@
 namespace OpenQA.Selenium.DevToolsGenerator.CodeGen
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
 
     /// <summary>
     /// Defines settings around templates
     /// </summary>
     public class CodeGenerationTemplateSettings
     {
-        [JsonProperty("templatePath")]
+        [JsonPropertyName("templatePath")]
         public string TemplatePath { get; set; }
 
-        [JsonProperty("outputPath")]
+        [JsonPropertyName("outputPath")]
         public string OutputPath { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/Converters/BooleanJsonConverter.cs b/third_party/dotnet/devtools/src/generator/Converters/BooleanJsonConverter.cs
index 99c2d4292a7fb..513fd55a0cc4b 100644
--- a/third_party/dotnet/devtools/src/generator/Converters/BooleanJsonConverter.cs
+++ b/third_party/dotnet/devtools/src/generator/Converters/BooleanJsonConverter.cs
@@ -1,68 +1,59 @@
 namespace OpenQA.Selenium.DevToolsGenerator.Converters
 {
-    using Newtonsoft.Json;
     using System;
+    using System.Text.Json;
+    using System.Text.Json.Serialization;
 
     /// <summary>
     /// Handles converting JSON string values into a C# boolean data type.
     /// </summary>
-    public class BooleanJsonConverter : JsonConverter
+    public class BooleanJsonConverter : JsonConverter<bool>
     {
-        /// <summary>
-        /// Determines whether this instance can convert the specified object type.
-        /// </summary>
-        /// <param name="objectType">Type of the object.</param>
-        /// <returns>
-        /// <c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
-        /// </returns>
-        public override bool CanConvert(Type objectType)
-        {
-            // Handle only boolean types.
-            return objectType == typeof(bool);
-        }
+        public override bool HandleNull => false;
 
-        /// <summary>
-        /// Reads the JSON representation of the object.
-        /// </summary>
-        /// <param name="reader">The <see cref="T:Newtonsoft.Json.JsonReader"/> to read from.</param>
-        /// <param name="objectType">Type of the object.</param>
-        /// <param name="existingValue">The existing value of object being read.</param>
-        /// <param name="serializer">The calling serializer.</param>
-        /// <returns>
-        /// The object value.
-        /// </returns>
-        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        public override bool Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            switch (reader.Value.ToString().ToLower().Trim())
+            switch (reader.TokenType)
             {
-                case "true":
-                case "yes":
-                case "y":
-                case "1":
+                case JsonTokenType.True:
                     return true;
-                case "false":
-                case "no":
-                case "n":
-                case "0":
+
+                case JsonTokenType.False:
                     return false;
-            }
 
-            // If we reach here, we're pretty much going to throw an error so let's let Json.NET throw it's pretty-fied error message.
-            return new JsonSerializer().Deserialize(reader, objectType);
-        }
+                case JsonTokenType.String:
+                    string boolString = reader.GetString()!;
+                    if (bool.TryParse(boolString, out bool b))
+                    {
+                        return b;
+                    }
+
+                    boolString = boolString.ToLowerInvariant();
 
-        /// <summary>
-        /// Specifies that this converter will not participate in writing results.
-        /// </summary>
-        public override bool CanWrite => false;
+                    if (boolString.AsSpan().Trim().SequenceEqual("yes".AsSpan()) ||
+                        boolString.AsSpan().Trim().SequenceEqual("y".AsSpan()) ||
+                        boolString.AsSpan().Trim().SequenceEqual("1".AsSpan()))
+                    {
+                        return true;
+                    }
+
+                    if (boolString.AsSpan().Trim().SequenceEqual("no".AsSpan()) ||
+                       boolString.AsSpan().Trim().SequenceEqual("n".AsSpan()) ||
+                       boolString.AsSpan().Trim().SequenceEqual("0".AsSpan()))
+                    {
+                        return false;
+                    }
+
+                    throw new JsonException();
+
+                default:
+                    throw new JsonException();
+            }
+        }
 
-        /// <summary>
-        /// Writes the JSON representation of the object.
-        /// </summary>
-        /// <param name="writer">The <see cref="T:Newtonsoft.Json.JsonWriter"/> to write to.</param><param name="value">The value.</param><param name="serializer">The calling serializer.</param>
-        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        public override void Write(Utf8JsonWriter writer, bool value, JsonSerializerOptions options)
         {
-            throw new NotSupportedException();
+            writer.WriteBooleanValue(value);
         }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/DevToolsGenerator.csproj b/third_party/dotnet/devtools/src/generator/DevToolsGenerator.csproj
index 8c053d83391fd..9c32a512b6730 100644
--- a/third_party/dotnet/devtools/src/generator/DevToolsGenerator.csproj
+++ b/third_party/dotnet/devtools/src/generator/DevToolsGenerator.csproj
@@ -2,8 +2,9 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net60</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <RootNamespace>OpenQA.Selenium.DevToolsGenerator</RootNamespace>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
@@ -19,7 +20,6 @@
     <PackageReference Include="Handlebars.Net" Version="1.11.5" />
     <PackageReference Include="Humanizer.Core" Version="2.14.1" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="3.1.32" />
-    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
   </ItemGroup>
 
 </Project>
diff --git a/third_party/dotnet/devtools/src/generator/Program.cs b/third_party/dotnet/devtools/src/generator/Program.cs
index a2aded339afb1..32cdfc52b5272 100644
--- a/third_party/dotnet/devtools/src/generator/Program.cs
+++ b/third_party/dotnet/devtools/src/generator/Program.cs
@@ -3,10 +3,11 @@
 using System.Text;
 using CommandLine;
 using Microsoft.Extensions.DependencyInjection;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
+using System.Text.Json.Serialization;
 using OpenQA.Selenium.DevToolsGenerator.CodeGen;
 using OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition;
+using System.Text.Json;
+using System.Text.Json.Nodes;
 
 namespace OpenQA.Selenium.DevToolsGenerator
 {
@@ -24,7 +25,7 @@ static int Main(string[] args)
             }
 
             var settingsJson = File.ReadAllText(cliArguments.Settings);
-            var settings = JsonConvert.DeserializeObject<CodeGenerationSettings>(settingsJson);
+            var settings = JsonSerializer.Deserialize<CodeGenerationSettings>(settingsJson);
             if (!string.IsNullOrEmpty(cliArguments.TemplatesPath))
             {
                 settings.TemplatesPath = cliArguments.TemplatesPath;
@@ -48,7 +49,7 @@ static int Main(string[] args)
 
             var protocolDefinitionData = GetProtocolDefinitionData(cliArguments);
 
-            var protocolDefinition = protocolDefinitionData.ToObject<ProtocolDefinition.ProtocolDefinition>(new JsonSerializer() { MetadataPropertyHandling = MetadataPropertyHandling.Ignore });
+            var protocolDefinition = protocolDefinitionData.Deserialize<ProtocolDefinition.ProtocolDefinition>(new JsonSerializerOptions() { ReferenceHandler = ReferenceHandler.IgnoreCycles });
 
             //Begin the code generation process.
             if (!cliArguments.Quiet)
@@ -113,9 +114,9 @@ static int Main(string[] args)
         /// </summary>
         /// <param name="args"></param>
         /// <returns></returns>
-        public static JObject GetProtocolDefinitionData(CommandLineOptions args)
+        public static JsonObject GetProtocolDefinitionData(CommandLineOptions args)
         {
-            JObject protocolData;
+            JsonObject protocolData;
             string browserProtocolPath = args.BrowserProtocolPath;
             if (!File.Exists(browserProtocolPath))
             {
@@ -134,15 +135,15 @@ public static JObject GetProtocolDefinitionData(CommandLineOptions args)
                 }
             }
 
-            JObject browserProtocol = JObject.Parse(File.ReadAllText(browserProtocolPath));
-            JObject jsProtocol = JObject.Parse(File.ReadAllText(jsProtocolPath));
+            JsonObject browserProtocol = JsonNode.Parse(File.ReadAllText(browserProtocolPath)).AsObject();
+            JsonObject jsProtocol = JsonNode.Parse(File.ReadAllText(jsProtocolPath)).AsObject();
 
             ProtocolVersionDefinition currentVersion = new ProtocolVersionDefinition();
             currentVersion.ProtocolVersion = "1.3";
             currentVersion.Browser = "Chrome/86.0";
 
             protocolData = MergeJavaScriptProtocolDefinitions(browserProtocol, jsProtocol);
-            protocolData["browserVersion"] = JToken.FromObject(currentVersion);
+            protocolData["browserVersion"] = JsonSerializer.SerializeToNode(currentVersion);
 
             return protocolData;
         }
@@ -153,7 +154,7 @@ public static JObject GetProtocolDefinitionData(CommandLineOptions args)
         /// <param name="browserProtocol"></param>
         /// <param name="jsProtocol"></param>
         /// <returns></returns>
-        public static JObject MergeJavaScriptProtocolDefinitions(JObject browserProtocol, JObject jsProtocol)
+        public static JsonObject MergeJavaScriptProtocolDefinitions(JsonObject? browserProtocol, JsonObject? jsProtocol)
         {
             //Merge the 2 protocols together.
             if (jsProtocol["version"]["majorVersion"] != browserProtocol["version"]["majorVersion"] ||
@@ -162,11 +163,11 @@ public static JObject MergeJavaScriptProtocolDefinitions(JObject browserProtocol
                 throw new InvalidOperationException("Protocol mismatch -- The WebKit and V8 protocol versions should match.");
             }
 
-            var result = browserProtocol.DeepClone() as JObject;
-            foreach (var domain in jsProtocol["domains"])
+            var result = browserProtocol.DeepClone().AsObject();
+            foreach (var domain in jsProtocol["domains"].AsArray())
             {
-                JArray jDomains = (JArray)result["domains"];
-                jDomains.Add(domain);
+                JsonArray jDomains = result["domains"].AsArray();
+                jDomains.Add(domain.DeepClone());
             }
 
             return result;
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/CommandDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/CommandDefinition.cs
index 9d7dec364c5ad..9a9c900b24d01 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/CommandDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/CommandDefinition.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System.Collections.Generic;
     using System.Collections.ObjectModel;
 
@@ -14,16 +14,16 @@ public CommandDefinition()
             Returns = new Collection<TypeDefinition>();
         }
 
-        [JsonProperty(PropertyName = "handlers")]
+        [JsonPropertyName("handlers")]
         public ICollection<string> Handlers { get; set; }
 
-        [JsonProperty(PropertyName = "parameters")]
+        [JsonPropertyName("parameters")]
         public ICollection<TypeDefinition> Parameters { get; set; }
 
-        [JsonProperty(PropertyName = "returns")]
+        [JsonPropertyName("returns")]
         public ICollection<TypeDefinition> Returns { get; set; }
 
-        [JsonProperty(PropertyName = "redirect")]
+        [JsonPropertyName("redirect")]
         public string Redirect { get; set; }
 
         [JsonIgnore]
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/DomainDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/DomainDefinition.cs
index 7c461f3277676..e66f36b82487a 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/DomainDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/DomainDefinition.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System.Collections.Generic;
     using System.Collections.ObjectModel;
 
@@ -15,19 +15,19 @@ public DomainDefinition()
             Commands = new Collection<CommandDefinition>();
         }
 
-        [JsonProperty(PropertyName = "domain")]
+        [JsonPropertyName("domain")]
         public override string Name { get; set; }
 
-        [JsonProperty(PropertyName = "types")]
+        [JsonPropertyName("types")]
         public ICollection<TypeDefinition> Types { get; set; }
 
-        [JsonProperty(PropertyName = "commands")]
+        [JsonPropertyName("commands")]
         public ICollection<CommandDefinition> Commands { get; set; }
 
-        [JsonProperty(PropertyName = "events")]
+        [JsonPropertyName("events")]
         public ICollection<EventDefinition> Events { get; set; }
 
-        [JsonProperty(PropertyName = "dependencies")]
+        [JsonPropertyName("dependencies")]
         public ICollection<string> Dependencies { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/EventDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/EventDefinition.cs
index ba0d19a661b34..b005742a6a378 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/EventDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/EventDefinition.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System.Collections.Generic;
     using System.Collections.ObjectModel;
 
@@ -11,7 +11,7 @@ public EventDefinition()
             Parameters = new Collection<TypeDefinition>();
         }
 
-        [JsonProperty(PropertyName = "parameters")]
+        [JsonPropertyName("parameters")]
         public ICollection<TypeDefinition> Parameters { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinition.cs
index 487b18e45ae27..cc7757b8d4a58 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinition.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System.Collections.Generic;
     using System.Collections.ObjectModel;
 
@@ -11,13 +11,16 @@ public ProtocolDefinition()
             Domains = new Collection<DomainDefinition>();
         }
 
-        [JsonProperty(PropertyName = "browserVersion", Required = Required.Always)]
+        [JsonPropertyName("browserVersion")]
+        [JsonRequired]
         public ProtocolVersionDefinition BrowserVersion { get; set; }
 
-        [JsonProperty(PropertyName = "version", Required = Required.Always)]
+        [JsonPropertyName("version")]
+        [JsonRequired]
         public Version Version { get; set; }
 
-        [JsonProperty(PropertyName = "domains", Required = Required.Always)]
+        [JsonPropertyName("domains")]
+        [JsonRequired]
         public ICollection<DomainDefinition> Domains { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinitionItem.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinitionItem.cs
index 75bdf196f993f..7310359e2f62c 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinitionItem.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolDefinitionItem.cs
@@ -1,12 +1,12 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using OpenQA.Selenium.DevToolsGenerator.Converters;
 
     public abstract class ProtocolDefinitionItem : IDefinition
     {
 
-        [JsonProperty(PropertyName = "deprecated")]
+        [JsonPropertyName("deprecated")]
         public bool Deprecated { get; set; }
 
         public string Description
@@ -15,11 +15,11 @@ public string Description
             set => InitialDescription = value;
         }
 
-        [JsonProperty(PropertyName = "experimental")]
+        [JsonPropertyName("experimental")]
         [JsonConverter(typeof(BooleanJsonConverter))]
         public bool Experimental { get; set; }
 
-        [JsonProperty(PropertyName = "name")]
+        [JsonPropertyName("name")]
         public virtual string Name { get; set; }
 
         public override string ToString()
@@ -27,7 +27,7 @@ public override string ToString()
             return Name;
         }
 
-        [JsonProperty(PropertyName = "description")]
+        [JsonPropertyName("description")]
         protected string InitialDescription { get; set; }
     }
 }
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolVersionDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolVersionDefinition.cs
index 172f9bd5f47c7..a69bd450025b0 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolVersionDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/ProtocolVersionDefinition.cs
@@ -1,4 +1,4 @@
-using Newtonsoft.Json;
+using System.Text.Json.Serialization;
 using System;
 using System.Collections.Generic;
 using System.Text;
@@ -11,7 +11,7 @@ namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
     /// </summary>
     public class ProtocolVersionDefinition
     {
-        [JsonProperty(PropertyName = "Browser")]
+        [JsonPropertyName("Browser")]
         public string Browser { get; set; }
 
         [JsonIgnore]
@@ -20,13 +20,13 @@ public class ProtocolVersionDefinition
         [JsonIgnore]
         public string BrowserMajorVersion => Regex.Match(Browser, ".*/(\\d+)\\..*").Groups[1].Value;
 
-        [JsonProperty(PropertyName = "Protocol-Version")]
+        [JsonPropertyName("Protocol-Version")]
         public string ProtocolVersion { get; set; }
 
-        [JsonProperty(PropertyName = "User-Agent")]
+        [JsonPropertyName("User-Agent")]
         public string UserAgent { get; set; }
 
-        [JsonProperty(PropertyName = "V8-Version")]
+        [JsonPropertyName("V8-Version")]
         public string V8Version { get; set; }
 
         [JsonIgnore]
@@ -46,7 +46,7 @@ public string V8VersionNumber
             }
         }
 
-        [JsonProperty(PropertyName = "WebKit-Version")]
+        [JsonPropertyName("WebKit-Version")]
         public string WebKitVersion { get; set; }
 
         [JsonIgnore]
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/TypeDefinition.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/TypeDefinition.cs
index 0c1948b0c356c..90452390914d8 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/TypeDefinition.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/TypeDefinition.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using OpenQA.Selenium.DevToolsGenerator.Converters;
     using System;
     using System.Collections.Generic;
@@ -14,31 +14,31 @@ public TypeDefinition()
             Properties = new Collection<TypeDefinition>();
         }
 
-        [JsonProperty(PropertyName = "id")]
+        [JsonPropertyName("id")]
         public string Id { get; set; }
 
-        [JsonProperty(PropertyName = "type")]
+        [JsonPropertyName("type")]
         public string Type { get; set; }
 
-        [JsonProperty(PropertyName = "enum")]
+        [JsonPropertyName("enum")]
         public ICollection<string> Enum { get; set; }
 
-        [JsonProperty(PropertyName = "properties")]
+        [JsonPropertyName("properties")]
         public ICollection<TypeDefinition> Properties { get; set; }
 
-        [JsonProperty(PropertyName = "items")]
+        [JsonPropertyName("items")]
         public TypeDefinition Items { get; set; }
 
-        [JsonProperty(PropertyName = "minItems")]
+        [JsonPropertyName("minItems")]
         public int MinItems { get; set; }
 
-        [JsonProperty(PropertyName = "maxItems")]
+        [JsonPropertyName("maxItems")]
         public int MaxItems { get; set; }
 
-        [JsonProperty(PropertyName = "$ref")]
+        [JsonPropertyName("$ref")]
         public string TypeReference { get; set; }
 
-        [JsonProperty(PropertyName = "optional")]
+        [JsonPropertyName("optional")]
         [JsonConverter(typeof(BooleanJsonConverter))]
         public bool Optional { get; set; }
 
diff --git a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/Version.cs b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/Version.cs
index efbde86ee9ee2..6ccf659057bac 100644
--- a/third_party/dotnet/devtools/src/generator/ProtocolDefinition/Version.cs
+++ b/third_party/dotnet/devtools/src/generator/ProtocolDefinition/Version.cs
@@ -1,6 +1,6 @@
 namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
 {
-    using Newtonsoft.Json;
+    using System.Text.Json.Serialization;
     using System;
 
     /// <summary>
@@ -8,10 +8,10 @@ namespace OpenQA.Selenium.DevToolsGenerator.ProtocolDefinition
     /// </summary>
     public sealed class Version : IComparable<Version>
     {
-        [JsonProperty(PropertyName = "major")]
+        [JsonPropertyName("major")]
         public string Major { get; set; }
 
-        [JsonProperty(PropertyName = "minor")]
+        [JsonPropertyName("minor")]
         public string Minor { get; set; }
 
         public int CompareTo(Version other)
diff --git a/third_party/dotnet/devtools/src/generator/Templates/project.hbs b/third_party/dotnet/devtools/src/generator/Templates/project.hbs
index 1b8a4fa3994b7..9768e1a26126c 100644
--- a/third_party/dotnet/devtools/src/generator/Templates/project.hbs
+++ b/third_party/dotnet/devtools/src/generator/Templates/project.hbs
@@ -3,6 +3,7 @@
     <PropertyGroup>
         <TargetFrameworks>net45;net46;net47;netstandard2.0</TargetFrameworks>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+        <Nullable>annotations</Nullable>
         <Version>{{chromeVersion.BrowserVersion}}{{#if runtimeVersion}}-{{runtimeVersion}}{{/if}}</Version>
         <Authors>Sean McLellan</Authors>
         <Company>BaristaLabs, LLC</Company>