diff --git a/samples/IdentitySample.Mvc/Startup.cs b/samples/IdentitySample.Mvc/Startup.cs
index 5b5641f6ea..2b550e0e83 100644
--- a/samples/IdentitySample.Mvc/Startup.cs
+++ b/samples/IdentitySample.Mvc/Startup.cs
@@ -15,7 +15,7 @@ namespace IdentitySamples
 {
     public class Startup
     {
-        public void Configure(IBuilder app)
+        public void Configure(IApplicationBuilder app)
         {
             /* Adding IConfiguration as a service in the IoC to avoid instantiating Configuration again.
                  * Below code demonstrates usage of multiple configuration sources. For instance a setting say 'setting1' is found in both the registered sources, 
diff --git a/src/Microsoft.AspNet.Identity.Authentication/BuilderExtensions.cs b/src/Microsoft.AspNet.Identity.Authentication/BuilderExtensions.cs
index 1125750ed4..892513ed58 100644
--- a/src/Microsoft.AspNet.Identity.Authentication/BuilderExtensions.cs
+++ b/src/Microsoft.AspNet.Identity.Authentication/BuilderExtensions.cs
@@ -11,7 +11,7 @@ namespace Microsoft.AspNet.Builder
     /// </summary>
     public static class BuilderExtensions
     {
-        public static IBuilder UseTwoFactorSignInCookies(this IBuilder builder)
+        public static IApplicationBuilder UseTwoFactorSignInCookies(this IApplicationBuilder builder)
         {
             // TODO: expose some way for them to customize these cookie lifetimes?
             builder.UseCookieAuthentication(new CookieAuthenticationOptions
diff --git a/test/Microsoft.AspNet.Identity.Authentication.Test/HttpSignInTest.cs b/test/Microsoft.AspNet.Identity.Authentication.Test/HttpSignInTest.cs
index 4da411e5d1..e2463670d5 100644
--- a/test/Microsoft.AspNet.Identity.Authentication.Test/HttpSignInTest.cs
+++ b/test/Microsoft.AspNet.Identity.Authentication.Test/HttpSignInTest.cs
@@ -25,7 +25,7 @@ namespace Microsoft.AspNet.Identity.Authentication.Test
         //[InlineData(false)]
         //public async Task VerifyAccountControllerSignInFunctional(bool isPersistent)
         //{
-        //    IBuilder app = new Builder(new ServiceCollection().BuildServiceProvider());
+        //    var app = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
         //    app.UseCookieAuthentication(new CookieAuthenticationOptions
         //    {
         //        AuthenticationType = ClaimsIdentityOptions.DefaultAuthenticationType
diff --git a/test/Microsoft.AspNet.Identity.InMemory.Test/HttpSignInTest.cs b/test/Microsoft.AspNet.Identity.InMemory.Test/HttpSignInTest.cs
index 6883c4f0b7..caceeb4fb1 100644
--- a/test/Microsoft.AspNet.Identity.InMemory.Test/HttpSignInTest.cs
+++ b/test/Microsoft.AspNet.Identity.InMemory.Test/HttpSignInTest.cs
@@ -25,7 +25,7 @@ namespace Microsoft.AspNet.Identity.InMemory.Test
         [InlineData(false)]
         public async Task VerifyAccountControllerSignIn(bool isPersistent)
         {
-            IBuilder app = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var app = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
             app.UseCookieAuthentication(new CookieAuthenticationOptions
             {
                 AuthenticationType = ClaimsIdentityOptions.DefaultAuthenticationType
diff --git a/test/Microsoft.AspNet.Identity.InMemory.Test/StartupTest.cs b/test/Microsoft.AspNet.Identity.InMemory.Test/StartupTest.cs
index 62a32f956f..899117a67a 100644
--- a/test/Microsoft.AspNet.Identity.InMemory.Test/StartupTest.cs
+++ b/test/Microsoft.AspNet.Identity.InMemory.Test/StartupTest.cs
@@ -19,7 +19,7 @@ namespace Microsoft.AspNet.Identity.InMemory.Test
         [Fact]
         public async Task EnsureStartupUsageWorks()
         {
-            var builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services => services.AddIdentity<ApplicationUser>().AddInMemory());
 
@@ -39,7 +39,7 @@ namespace Microsoft.AspNet.Identity.InMemory.Test
         [Fact]
         public void VerifyUseInMemoryLifetimes()
         {
-            var builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
             builder.UseServices(services => services.AddIdentity<ApplicationUser>().AddInMemory());
 
             var userStore = builder.ApplicationServices.GetService<IUserStore<ApplicationUser>>();
diff --git a/test/Microsoft.AspNet.Identity.SqlServer.Test/DefaultPocoTest.cs b/test/Microsoft.AspNet.Identity.SqlServer.Test/DefaultPocoTest.cs
index 2269843c2e..465b2edede 100644
--- a/test/Microsoft.AspNet.Identity.SqlServer.Test/DefaultPocoTest.cs
+++ b/test/Microsoft.AspNet.Identity.SqlServer.Test/DefaultPocoTest.cs
@@ -50,7 +50,7 @@ namespace Microsoft.AspNet.Identity.SqlServer.Test
         public async Task EnsureStartupUsageWorks()
         {
             var context = CreateContext(true);
-            IBuilder builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services =>
             {
diff --git a/test/Microsoft.AspNet.Identity.SqlServer.Test/SqlStoreTestBase.cs b/test/Microsoft.AspNet.Identity.SqlServer.Test/SqlStoreTestBase.cs
index e6c89a0677..eacc95d6ad 100644
--- a/test/Microsoft.AspNet.Identity.SqlServer.Test/SqlStoreTestBase.cs
+++ b/test/Microsoft.AspNet.Identity.SqlServer.Test/SqlStoreTestBase.cs
@@ -107,7 +107,7 @@ namespace Microsoft.AspNet.Identity.SqlServer.Test
         public async Task EnsureStartupUsageWorks()
         {
             EnsureDatabase();
-            IBuilder builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services =>
             {
@@ -134,7 +134,7 @@ namespace Microsoft.AspNet.Identity.SqlServer.Test
         public async Task EnsureStartupOptionsChangeWorks()
         {
             EnsureDatabase();
-            IBuilder builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services =>
             {
diff --git a/test/Microsoft.AspNet.Identity.SqlServer.Test/UserStoreTest.cs b/test/Microsoft.AspNet.Identity.SqlServer.Test/UserStoreTest.cs
index 1be62f5c14..4bd79f6296 100644
--- a/test/Microsoft.AspNet.Identity.SqlServer.Test/UserStoreTest.cs
+++ b/test/Microsoft.AspNet.Identity.SqlServer.Test/UserStoreTest.cs
@@ -61,7 +61,7 @@ namespace Microsoft.AspNet.Identity.SqlServer.Test
         public async Task EnsureStartupUsageWorks()
         {
             EnsureDatabase();
-            IBuilder builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services =>
             {
@@ -88,7 +88,7 @@ namespace Microsoft.AspNet.Identity.SqlServer.Test
         public async Task EnsureStartupOptionsChangeWorks()
         {
             EnsureDatabase();
-            IBuilder builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
 
             builder.UseServices(services =>
             {
diff --git a/test/Microsoft.AspNet.Identity.Test/IdentityOptionsTest.cs b/test/Microsoft.AspNet.Identity.Test/IdentityOptionsTest.cs
index 094807548c..240992d95d 100644
--- a/test/Microsoft.AspNet.Identity.Test/IdentityOptionsTest.cs
+++ b/test/Microsoft.AspNet.Identity.Test/IdentityOptionsTest.cs
@@ -100,7 +100,7 @@ namespace Microsoft.AspNet.Identity.Test
         [Fact]
         public void CanCustomizeIdentityOptions()
         {
-            var builder = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var builder = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
             builder.UseServices(services =>
             {
                 services.AddIdentity<IdentityUser>();
@@ -124,7 +124,7 @@ namespace Microsoft.AspNet.Identity.Test
         [Fact]
         public void CanSetupIdentityOptions()
         {
-            var app = new Builder.Builder(new ServiceCollection().BuildServiceProvider());
+            var app = new ApplicationBuilder(new ServiceCollection().BuildServiceProvider());
             app.UseServices(services =>
             {
                 services.AddIdentity<IdentityUser>().SetupOptions(options => options.User.RequireUniqueEmail = true);