diff --git a/dotnet/src/webdriver/DevTools/DevToolsExtensionMethods.cs b/dotnet/src/webdriver/DevTools/DevToolsExtensionMethods.cs
index 21711f1822b75..0471eee435529 100644
--- a/dotnet/src/webdriver/DevTools/DevToolsExtensionMethods.cs
+++ b/dotnet/src/webdriver/DevTools/DevToolsExtensionMethods.cs
@@ -17,6 +17,8 @@
 // under the License.
 // </copyright>
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
diff --git a/dotnet/src/webdriver/DevTools/DevToolsOptions.cs b/dotnet/src/webdriver/DevTools/DevToolsOptions.cs
index e0b5f365261a7..e3222fba48315 100644
--- a/dotnet/src/webdriver/DevTools/DevToolsOptions.cs
+++ b/dotnet/src/webdriver/DevTools/DevToolsOptions.cs
@@ -17,6 +17,8 @@
 // under the License.
 // </copyright>
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
diff --git a/dotnet/src/webdriver/DevTools/DevToolsSessionDomains.cs b/dotnet/src/webdriver/DevTools/DevToolsSessionDomains.cs
index 96d1521f92500..a7c6825e8a659 100644
--- a/dotnet/src/webdriver/DevTools/DevToolsSessionDomains.cs
+++ b/dotnet/src/webdriver/DevTools/DevToolsSessionDomains.cs
@@ -17,6 +17,8 @@
 // under the License.
 // </copyright>
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
@@ -24,8 +26,6 @@ namespace OpenQA.Selenium.DevTools
     /// </summary>
     public abstract class DevToolsSessionDomains
     {
-        private CommandResponseTypeMap responseTypeMap = new CommandResponseTypeMap();
-
         /// <summary>
         /// Initializes a new instance of the <see cref="DevToolsSessionDomains"/> class.
         /// </summary>
@@ -37,7 +37,7 @@ protected DevToolsSessionDomains()
         /// <summary>
         /// Gets the <see cref="CommandResponseTypeMap"/> containing information about the types returned by DevTools Protocol commands.,
         /// </summary>
-        internal CommandResponseTypeMap ResponseTypeMap => this.responseTypeMap;
+        internal CommandResponseTypeMap ResponseTypeMap { get; } = new CommandResponseTypeMap();
 
         /// <summary>
         /// Populates the command response type map.
diff --git a/dotnet/src/webdriver/DevTools/DevToolsSessionEventReceivedEventArgs.cs b/dotnet/src/webdriver/DevTools/DevToolsSessionEventReceivedEventArgs.cs
index 4840c7a366a7f..80ce25cd78403 100644
--- a/dotnet/src/webdriver/DevTools/DevToolsSessionEventReceivedEventArgs.cs
+++ b/dotnet/src/webdriver/DevTools/DevToolsSessionEventReceivedEventArgs.cs
@@ -21,6 +21,8 @@
 using System.Text.Json;
 using System.Text.Json.Nodes;
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
@@ -44,16 +46,16 @@ public DevToolsEventReceivedEventArgs(string domainName, string eventName, JsonE
         /// <summary>
         /// Gets the domain on which the event is to be raised.
         /// </summary>
-        public string DomainName { get; private set; }
+        public string DomainName { get; }
 
         /// <summary>
         /// Gets the name of the event to be raised.
         /// </summary>
-        public string EventName { get; private set; }
+        public string EventName { get; }
 
         /// <summary>
         /// Gets the data with which the event is to be raised.
         /// </summary>
-        public JsonElement EventData { get; private set; }
+        public JsonElement EventData { get; }
     }
 }
diff --git a/dotnet/src/webdriver/DevTools/DevToolsSessionLogMessageEventArgs.cs b/dotnet/src/webdriver/DevTools/DevToolsSessionLogMessageEventArgs.cs
index b3f0bd5ad9fd8..c2e233a695e2a 100644
--- a/dotnet/src/webdriver/DevTools/DevToolsSessionLogMessageEventArgs.cs
+++ b/dotnet/src/webdriver/DevTools/DevToolsSessionLogMessageEventArgs.cs
@@ -19,6 +19,8 @@
 
 using System;
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
diff --git a/dotnet/src/webdriver/DevTools/ExceptionThrownEventArgs.cs b/dotnet/src/webdriver/DevTools/ExceptionThrownEventArgs.cs
index dadd804a4de58..8c1d92211a539 100644
--- a/dotnet/src/webdriver/DevTools/ExceptionThrownEventArgs.cs
+++ b/dotnet/src/webdriver/DevTools/ExceptionThrownEventArgs.cs
@@ -19,6 +19,8 @@
 
 using System;
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
@@ -26,14 +28,25 @@ namespace OpenQA.Selenium.DevTools
     /// </summary>
     public class ExceptionThrownEventArgs : EventArgs
     {
+        /// <summary>
+        /// Initializes new instance of the <see cref="ExceptionThrownEventArgs"/> type.
+        /// </summary>
+        /// <param name="timestamp">The time stamp of the exception.</param>
+        /// <param name="message">The text of the exception.</param>
+        public ExceptionThrownEventArgs(DateTime timestamp, string message)
+        {
+            Timestamp = timestamp;
+            Message = message;
+        }
+
         /// <summary>
         /// Gets the time stamp of the exception.
         /// </summary>
-        public DateTime Timestamp { get; internal set; }
+        public DateTime Timestamp { get; }
 
         /// <summary>
         /// Gets the text of the exception.
         /// </summary>
-        public string Message { get; internal set; }
+        public string Message { get; }
     }
 }
diff --git a/dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs b/dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs
index 7d109f5801466..58d23db40579d 100644
--- a/dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs
+++ b/dotnet/src/webdriver/DevTools/Json/JsonEnumMemberConverter.cs
@@ -24,6 +24,8 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools.Json
 {
     internal sealed class JsonEnumMemberConverter<TEnum> : JsonConverter<TEnum>
@@ -63,7 +65,7 @@ public JsonEnumMemberConverter()
 
         public override TEnum Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            var stringValue = reader.GetString();
+            var stringValue = reader.GetString() ?? throw new JsonException("Could not read an enum string from \"null\"");
 
             if (_stringToEnum.TryGetValue(stringValue, out var enumValue))
             {
diff --git a/dotnet/src/webdriver/DevTools/ResponsePausedEventArgs.cs b/dotnet/src/webdriver/DevTools/ResponsePausedEventArgs.cs
index 417a1e4b43680..a38ccc40ec285 100644
--- a/dotnet/src/webdriver/DevTools/ResponsePausedEventArgs.cs
+++ b/dotnet/src/webdriver/DevTools/ResponsePausedEventArgs.cs
@@ -19,6 +19,8 @@
 
 using System;
 
+#nullable enable
+
 namespace OpenQA.Selenium.DevTools
 {
     /// <summary>
diff --git a/dotnet/src/webdriver/DevTools/v130/V130JavaScript.cs b/dotnet/src/webdriver/DevTools/v130/V130JavaScript.cs
index be462967b0f0b..3f5946ed51033 100644
--- a/dotnet/src/webdriver/DevTools/v130/V130JavaScript.cs
+++ b/dotnet/src/webdriver/DevTools/v130/V130JavaScript.cs
@@ -153,11 +153,11 @@ private void OnRuntimeBindingCalled(object sender, Runtime.BindingCalledEventArg
         private void OnRuntimeExceptionThrown(object sender, Runtime.ExceptionThrownEventArgs e)
         {
             // TODO: Collect stack trace elements
-            var wrapped = new ExceptionThrownEventArgs()
-            {
-                Timestamp = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
-                Message = e.ExceptionDetails.Text
-            };
+            var wrapped = new ExceptionThrownEventArgs
+            (
+                timestamp: new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
+                message: e.ExceptionDetails.Text
+            );
 
             this.OnExceptionThrown(wrapped);
         }
diff --git a/dotnet/src/webdriver/DevTools/v131/V131JavaScript.cs b/dotnet/src/webdriver/DevTools/v131/V131JavaScript.cs
index 873c03cc5360b..d523202a85086 100644
--- a/dotnet/src/webdriver/DevTools/v131/V131JavaScript.cs
+++ b/dotnet/src/webdriver/DevTools/v131/V131JavaScript.cs
@@ -153,11 +153,11 @@ private void OnRuntimeBindingCalled(object sender, Runtime.BindingCalledEventArg
         private void OnRuntimeExceptionThrown(object sender, Runtime.ExceptionThrownEventArgs e)
         {
             // TODO: Collect stack trace elements
-            var wrapped = new ExceptionThrownEventArgs()
-            {
-                Timestamp = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
-                Message = e.ExceptionDetails.Text
-            };
+            var wrapped = new ExceptionThrownEventArgs
+            (
+                timestamp: new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
+                message: e.ExceptionDetails.Text
+            );
 
             this.OnExceptionThrown(wrapped);
         }
diff --git a/dotnet/src/webdriver/DevTools/v132/V132JavaScript.cs b/dotnet/src/webdriver/DevTools/v132/V132JavaScript.cs
index 6e9a093d145dd..edbcdab9280a9 100644
--- a/dotnet/src/webdriver/DevTools/v132/V132JavaScript.cs
+++ b/dotnet/src/webdriver/DevTools/v132/V132JavaScript.cs
@@ -153,11 +153,11 @@ private void OnRuntimeBindingCalled(object sender, Runtime.BindingCalledEventArg
         private void OnRuntimeExceptionThrown(object sender, Runtime.ExceptionThrownEventArgs e)
         {
             // TODO: Collect stack trace elements
-            var wrapped = new ExceptionThrownEventArgs()
-            {
-                Timestamp = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
-                Message = e.ExceptionDetails.Text
-            };
+            var wrapped = new ExceptionThrownEventArgs
+            (
+                timestamp: new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
+                message: e.ExceptionDetails.Text
+            );
 
             this.OnExceptionThrown(wrapped);
         }
diff --git a/dotnet/src/webdriver/DevTools/v85/V85JavaScript.cs b/dotnet/src/webdriver/DevTools/v85/V85JavaScript.cs
index 570d05ada0c67..7a9cfbab234c5 100644
--- a/dotnet/src/webdriver/DevTools/v85/V85JavaScript.cs
+++ b/dotnet/src/webdriver/DevTools/v85/V85JavaScript.cs
@@ -153,11 +153,11 @@ private void OnRuntimeBindingCalled(object sender, Runtime.BindingCalledEventArg
         private void OnRuntimeExceptionThrown(object sender, Runtime.ExceptionThrownEventArgs e)
         {
             // TODO: Collect stack trace elements
-            var wrapped = new ExceptionThrownEventArgs()
-            {
-                Timestamp = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
-                Message = e.ExceptionDetails.Text
-            };
+            var wrapped = new ExceptionThrownEventArgs
+            (
+                timestamp: new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(e.Timestamp),
+                message: e.ExceptionDetails.Text
+            );
 
             this.OnExceptionThrown(wrapped);
         }