diff --git a/src/Microsoft.AspNet.Session/DistributedSession.cs b/src/Microsoft.AspNet.Session/DistributedSession.cs
index 2f5b5e6774..134dfcbe47 100644
--- a/src/Microsoft.AspNet.Session/DistributedSession.cs
+++ b/src/Microsoft.AspNet.Session/DistributedSession.cs
@@ -9,7 +9,6 @@ using System.Text;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Http.Features;
 using Microsoft.Extensions.Caching.Distributed;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNet.Session
@@ -29,9 +28,34 @@ namespace Microsoft.AspNet.Session
         private bool _loaded;
         private bool _isNewSessionKey;
 
-        public DistributedSession([NotNull] IDistributedCache cache, [NotNull] string sessionId, TimeSpan idleTimeout,
-            [NotNull] Func<bool> tryEstablishSession, [NotNull] ILoggerFactory loggerFactory, bool isNewSessionKey)
+        public DistributedSession(
+            IDistributedCache cache,
+            string sessionId,
+            TimeSpan idleTimeout,
+            Func<bool> tryEstablishSession,
+            ILoggerFactory loggerFactory,
+            bool isNewSessionKey)
         {
+            if (cache == null)
+            {
+                throw new ArgumentNullException(nameof(cache));
+            }
+
+            if (string.IsNullOrEmpty(sessionId))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(sessionId));
+            }
+
+            if (tryEstablishSession == null)
+            {
+                throw new ArgumentNullException(nameof(tryEstablishSession));
+            }
+
+            if (loggerFactory == null)
+            {
+                throw new ArgumentNullException(nameof(loggerFactory));
+            }
+
             _cache = cache;
             _sessionId = sessionId;
             _idleTimeout = idleTimeout;
@@ -56,8 +80,13 @@ namespace Microsoft.AspNet.Session
             return _store.TryGetValue(new EncodedKey(key), out value);
         }
 
-        public void Set(string key, [NotNull] byte[] value)
+        public void Set(string key, byte[] value)
         {
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
             var encodedKey = new EncodedKey(key);
             if (encodedKey.KeyBytes.Length > KeyLengthLimit)
             {
diff --git a/src/Microsoft.AspNet.Session/DistributedSessionStore.cs b/src/Microsoft.AspNet.Session/DistributedSessionStore.cs
index f6a0866de9..27b3b88372 100644
--- a/src/Microsoft.AspNet.Session/DistributedSessionStore.cs
+++ b/src/Microsoft.AspNet.Session/DistributedSessionStore.cs
@@ -4,7 +4,6 @@
 using System;
 using Microsoft.AspNet.Http.Features;
 using Microsoft.Extensions.Caching.Distributed;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNet.Session
@@ -14,8 +13,18 @@ namespace Microsoft.AspNet.Session
         private readonly IDistributedCache _cache;
         private readonly ILoggerFactory _loggerFactory;
 
-        public DistributedSessionStore([NotNull] IDistributedCache cache, [NotNull] ILoggerFactory loggerFactory)
+        public DistributedSessionStore(IDistributedCache cache, ILoggerFactory loggerFactory)
         {
+            if (cache == null)
+            {
+                throw new ArgumentNullException(nameof(cache));
+            }
+
+            if (loggerFactory == null)
+            {
+                throw new ArgumentNullException(nameof(loggerFactory));
+            }
+
             _cache = cache;
             _loggerFactory = loggerFactory;
         }
@@ -33,8 +42,18 @@ namespace Microsoft.AspNet.Session
             _cache.Connect();
         }
 
-        public ISession Create([NotNull] string sessionId, TimeSpan idleTimeout, [NotNull] Func<bool> tryEstablishSession, bool isNewSessionKey)
+        public ISession Create(string sessionId, TimeSpan idleTimeout, Func<bool> tryEstablishSession, bool isNewSessionKey)
         {
+            if (string.IsNullOrEmpty(sessionId))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(sessionId));
+            }
+
+            if (tryEstablishSession == null)
+            {
+                throw new ArgumentNullException(nameof(tryEstablishSession));
+            }
+
             return new DistributedSession(_cache, sessionId, idleTimeout, tryEstablishSession, _loggerFactory, isNewSessionKey);
         }
     }
diff --git a/src/Microsoft.AspNet.Session/Properties/Resources.Designer.cs b/src/Microsoft.AspNet.Session/Properties/Resources.Designer.cs
index e92a12995b..4ee53d8b6c 100644
--- a/src/Microsoft.AspNet.Session/Properties/Resources.Designer.cs
+++ b/src/Microsoft.AspNet.Session/Properties/Resources.Designer.cs
@@ -17,7 +17,7 @@ namespace Microsoft.AspNet.Session
         {
             get { return GetString("Exception_KeyLengthIsExceeded"); }
         }
-        
+
         /// <summary>
         /// The key cannot be longer than '{0}' when encoded with UTF-8.
         /// </summary>
@@ -33,7 +33,7 @@ namespace Microsoft.AspNet.Session
         {
             get { return GetString("Exception_InvalidSessionEstablishment"); }
         }
-        
+
         /// <summary>
         /// The session cannot be established after the response has started.
         /// </summary>
@@ -49,7 +49,7 @@ namespace Microsoft.AspNet.Session
         {
             get { return GetString("Exception_InvalidToSerializeIn2Bytes"); }
         }
-        
+
         /// <summary>
         /// The value cannot be serialized in two bytes.
         /// </summary>
@@ -57,7 +57,7 @@ namespace Microsoft.AspNet.Session
         {
             return GetString("Exception_InvalidToSerializeIn2Bytes");
         }
-        
+
         /// <summary>
         /// The value cannot be serialized in three bytes.
         /// </summary>
@@ -65,7 +65,7 @@ namespace Microsoft.AspNet.Session
         {
             get { return GetString("Exception_InvalidToSerializeIn3Bytes"); }
         }
-        
+
         /// <summary>
         /// The value cannot be serialized in three bytes.
         /// </summary>
@@ -73,7 +73,7 @@ namespace Microsoft.AspNet.Session
         {
             return GetString("Exception_InvalidToSerializeIn3Bytes");
         }
-        
+
         /// <summary>
         /// The value cannot be negative.
         /// </summary>
@@ -81,7 +81,7 @@ namespace Microsoft.AspNet.Session
         {
             get { return GetString("Exception_NumberShouldNotBeNegative"); }
         }
-        
+
         /// <summary>
         /// The value cannot be negative.
         /// </summary>
@@ -89,7 +89,23 @@ namespace Microsoft.AspNet.Session
         {
             return GetString("Exception_NumberShouldNotBeNegative");
         }
-                                 
+
+        /// <summary>
+        /// Argument cannot be null or empty string.
+        /// </summary>
+        internal static string ArgumentCannotBeNullOrEmpty
+        {
+            get { return GetString("ArgumentCannotBeNullOrEmpty"); }
+        }
+
+        /// <summary>
+        /// Argument cannot be null or empty string.
+        /// </summary>
+        internal static string FormatArgumentCannotBeNullOrEmpty()
+        {
+            return GetString("ArgumentCannotBeNullOrEmpty");
+        }
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);
@@ -107,4 +123,4 @@ namespace Microsoft.AspNet.Session
             return value;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Microsoft.AspNet.Session/Resources.resx b/src/Microsoft.AspNet.Session/Resources.resx
index 8212053460..5bb1c8e0bb 100644
--- a/src/Microsoft.AspNet.Session/Resources.resx
+++ b/src/Microsoft.AspNet.Session/Resources.resx
@@ -132,4 +132,7 @@
   <data name="Exception_NumberShouldNotBeNegative" xml:space="preserve">
     <value>The value cannot be negative.</value>
   </data>
+  <data name="ArgumentCannotBeNullOrEmpty" xml:space="preserve">
+    <value>Argument cannot be null or empty string.</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/src/Microsoft.AspNet.Session/SessionMiddleware.cs b/src/Microsoft.AspNet.Session/SessionMiddleware.cs
index 65294a2841..1abdcf4db4 100644
--- a/src/Microsoft.AspNet.Session/SessionMiddleware.cs
+++ b/src/Microsoft.AspNet.Session/SessionMiddleware.cs
@@ -7,7 +7,6 @@ using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Features;
-using Microsoft.Extensions.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.OptionsModel;
 
@@ -34,11 +33,31 @@ namespace Microsoft.AspNet.Session
         /// <param name="sessionStore">The <see cref="ISessionStore"/> representing the session store.</param>
         /// <param name="options">The session configuration options.</param>
         public SessionMiddleware(
-            [NotNull] RequestDelegate next,
-            [NotNull] ILoggerFactory loggerFactory,
-            [NotNull] ISessionStore sessionStore,
-            [NotNull] IOptions<SessionOptions> options)
+            RequestDelegate next,
+            ILoggerFactory loggerFactory,
+            ISessionStore sessionStore,
+            IOptions<SessionOptions> options)
         {
+            if (next == null)
+            {
+                throw new ArgumentNullException(nameof(next));
+            }
+
+            if (loggerFactory == null)
+            {
+                throw new ArgumentNullException(nameof(loggerFactory));
+            }
+
+            if (sessionStore == null)
+            {
+                throw new ArgumentNullException(nameof(sessionStore));
+            }
+
+            if (options == null)
+            {
+                throw new ArgumentNullException(nameof(options));
+            }
+
             _next = next;
             _logger = loggerFactory.CreateLogger<SessionMiddleware>();
             _options = options.Value;
diff --git a/src/Microsoft.AspNet.Session/SessionMiddlewareExtensions.cs b/src/Microsoft.AspNet.Session/SessionMiddlewareExtensions.cs
index d6f16d0dc7..96feb96721 100644
--- a/src/Microsoft.AspNet.Session/SessionMiddlewareExtensions.cs
+++ b/src/Microsoft.AspNet.Session/SessionMiddlewareExtensions.cs
@@ -1,8 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using Microsoft.AspNet.Session;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNet.Builder
 {
@@ -16,8 +16,13 @@ namespace Microsoft.AspNet.Builder
         /// </summary>
         /// <param name="app">The <see cref="IApplicationBuilder"/>.</param>
         /// <returns>The <see cref="IApplicationBuilder"/>.</returns>
-        public static IApplicationBuilder UseSession([NotNull] this IApplicationBuilder app)
+        public static IApplicationBuilder UseSession(this IApplicationBuilder app)
         {
+            if (app == null)
+            {
+                throw new ArgumentNullException(nameof(app));
+            }
+
             return app.UseMiddleware<SessionMiddleware>();
         }
     }
diff --git a/src/Microsoft.AspNet.Session/SessionServiceCollectionExtensions.cs b/src/Microsoft.AspNet.Session/SessionServiceCollectionExtensions.cs
index 31bd37ca8d..4f20017203 100644
--- a/src/Microsoft.AspNet.Session/SessionServiceCollectionExtensions.cs
+++ b/src/Microsoft.AspNet.Session/SessionServiceCollectionExtensions.cs
@@ -3,7 +3,6 @@
 
 using System;
 using Microsoft.AspNet.Session;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.Extensions.DependencyInjection
 {
@@ -17,8 +16,13 @@ namespace Microsoft.Extensions.DependencyInjection
         /// </summary>
         /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
         /// <returns>The <see cref="IServiceCollection"/>.</returns>
-        public static IServiceCollection AddSession([NotNull] this IServiceCollection services)
+        public static IServiceCollection AddSession(this IServiceCollection services)
         {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
             services.AddOptions();
             services.AddTransient<ISessionStore, DistributedSessionStore>();
             return services;
@@ -30,8 +34,13 @@ namespace Microsoft.Extensions.DependencyInjection
         /// <param name="services">The <see cref="IServiceCollection"/> to add the services to.</param>
         /// <param name="configure">The session options to configure the middleware with.</param>
         /// <returns>The <see cref="IServiceCollection"/>.</returns>
-        public static IServiceCollection AddSession([NotNull] this IServiceCollection services, Action<SessionOptions> configure)
+        public static IServiceCollection AddSession(this IServiceCollection services, Action<SessionOptions> configure)
         {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
             services.Configure(configure);
             return services.AddSession();
         }
diff --git a/src/Microsoft.AspNet.Session/project.json b/src/Microsoft.AspNet.Session/project.json
index cdd5db0e77..9058ae48f1 100644
--- a/src/Microsoft.AspNet.Session/project.json
+++ b/src/Microsoft.AspNet.Session/project.json
@@ -9,11 +9,11 @@
         "Microsoft.AspNet.Http.Abstractions": "1.0.0-*",
         "Microsoft.Extensions.Caching.Abstractions": "1.0.0-*",
         "Microsoft.Extensions.Logging.Abstractions": "1.0.0-*",
-        "Microsoft.Extensions.NotNullAttribute.Sources": { "type": "build", "version": "1.0.0-*" },
         "Microsoft.Extensions.OptionsModel": "1.0.0-*"
     },
     "compilationOptions": {
-        "allowUnsafe": true
+        "allowUnsafe": true,
+        "warningsAsErrors": true
     },
     "frameworks": {
         "dnx451": { },