diff --git a/src/Microsoft.AspNet.Diagnostics/DiagnosticsPageExtensions.cs b/src/Microsoft.AspNet.Diagnostics/DiagnosticsPageExtensions.cs
index e8d9e488e6..17da1ee340 100644
--- a/src/Microsoft.AspNet.Diagnostics/DiagnosticsPageExtensions.cs
+++ b/src/Microsoft.AspNet.Diagnostics/DiagnosticsPageExtensions.cs
@@ -6,6 +6,7 @@
 using System;
 using Microsoft.AspNet.Abstractions;
 using Microsoft.AspNet.Diagnostics;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -20,13 +21,8 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseDiagnosticsPage(this IApplicationBuilder builder, DiagnosticsPageOptions options)
+        public static IApplicationBuilder UseDiagnosticsPage([NotNull] this IApplicationBuilder builder, DiagnosticsPageOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
             return builder.Use(next => new DiagnosticsPageMiddleware(next, options).Invoke);
         }
 
diff --git a/src/Microsoft.AspNet.Diagnostics/ErrorPageExtensions.cs b/src/Microsoft.AspNet.Diagnostics/ErrorPageExtensions.cs
index f90fe7634b..707f7d20bf 100644
--- a/src/Microsoft.AspNet.Diagnostics/ErrorPageExtensions.cs
+++ b/src/Microsoft.AspNet.Diagnostics/ErrorPageExtensions.cs
@@ -3,6 +3,7 @@
 
 using System;
 using Microsoft.AspNet.Diagnostics;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -17,13 +18,8 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="builder"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseErrorPage(this IApplicationBuilder builder)
+        public static IApplicationBuilder UseErrorPage([NotNull] this IApplicationBuilder builder)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
             return builder.UseErrorPage(new ErrorPageOptions());
         }
 
@@ -34,12 +30,8 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseErrorPage(this IApplicationBuilder builder, ErrorPageOptions options)
+        public static IApplicationBuilder UseErrorPage([NotNull] this IApplicationBuilder builder, ErrorPageOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
             /* TODO: Development, Staging, or Production
             string appMode = new AppProperties(builder.Properties).Get<string>(Constants.HostAppMode);
             bool isDevMode = string.Equals(Constants.DevMode, appMode, StringComparison.Ordinal);*/
diff --git a/src/Microsoft.AspNet.Diagnostics/ErrorPageMiddleware.cs b/src/Microsoft.AspNet.Diagnostics/ErrorPageMiddleware.cs
index 97b5ee50c7..888bd42ef0 100644
--- a/src/Microsoft.AspNet.Diagnostics/ErrorPageMiddleware.cs
+++ b/src/Microsoft.AspNet.Diagnostics/ErrorPageMiddleware.cs
@@ -13,6 +13,7 @@ using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Diagnostics.Views;
 using Microsoft.AspNet.Http;
 using Microsoft.Framework.Runtime;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Diagnostics
 {
@@ -31,16 +32,8 @@ namespace Microsoft.AspNet.Diagnostics
         /// <param name="next"></param>
         /// <param name="options"></param>
         /// <param name="isDevMode"></param>
-        public ErrorPageMiddleware(RequestDelegate next, ErrorPageOptions options, bool isDevMode)
+        public ErrorPageMiddleware([NotNull] RequestDelegate next, [NotNull] ErrorPageOptions options, bool isDevMode)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
             if (isDevMode)
             {
                 options.SetDefaultVisibility(isVisible: true);
diff --git a/src/Microsoft.AspNet.Diagnostics/WelcomePageExtensions.cs b/src/Microsoft.AspNet.Diagnostics/WelcomePageExtensions.cs
index f297d52651..efb7ff54e5 100644
--- a/src/Microsoft.AspNet.Diagnostics/WelcomePageExtensions.cs
+++ b/src/Microsoft.AspNet.Diagnostics/WelcomePageExtensions.cs
@@ -5,6 +5,7 @@
 using System;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Diagnostics;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -19,13 +20,8 @@ namespace Microsoft.AspNet.Builder
         /// <param name="builder"></param>
         /// <param name="options"></param>
         /// <returns></returns>
-        public static IApplicationBuilder UseWelcomePage(this IApplicationBuilder builder, WelcomePageOptions options)
+        public static IApplicationBuilder UseWelcomePage([NotNull] this IApplicationBuilder builder, WelcomePageOptions options)
         {
-            if (builder == null)
-            {
-                throw new ArgumentNullException("builder");
-            }
-
             return builder.Use(next => new WelcomePageMiddleware(next, options).Invoke);
         }
 
diff --git a/src/Microsoft.AspNet.Diagnostics/WelcomePageMiddleware.cs b/src/Microsoft.AspNet.Diagnostics/WelcomePageMiddleware.cs
index e9a0848fa1..cb63792d4f 100644
--- a/src/Microsoft.AspNet.Diagnostics/WelcomePageMiddleware.cs
+++ b/src/Microsoft.AspNet.Diagnostics/WelcomePageMiddleware.cs
@@ -8,6 +8,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNet.Diagnostics.Views;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Http;
+using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Diagnostics
 {
@@ -24,17 +25,8 @@ namespace Microsoft.AspNet.Diagnostics
         /// </summary>
         /// <param name="next"></param>
         /// <param name="options"></param>
-        public WelcomePageMiddleware(RequestDelegate next, WelcomePageOptions options)
+        public WelcomePageMiddleware([NotNull] RequestDelegate next, [NotNull] WelcomePageOptions options)
         {
-            if (next == null)
-            {
-                throw new ArgumentNullException("next");
-            }
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
-
             _next = next;
             _options = options;
         }