diff --git a/yesod/scaffold/Application.hs.cg b/yesod/scaffold/Application.hs.cg
index 02d95819..6c9a5c65 100644
--- a/yesod/scaffold/Application.hs.cg
+++ b/yesod/scaffold/Application.hs.cg
@@ -12,6 +12,8 @@ import Foundation
 import Settings
 import Settings.StaticFiles (static)
 import Yesod.Auth
+import Yesod.Default.Config
+import Yesod.Default.Main
 import Yesod.Logger (Logger)
 import Database.Persist.~importGenericDB~
 import Data.ByteString (ByteString)
@@ -43,7 +45,7 @@ getRobotsR = return $ RepPlain $ toContent ("User-agent: *" :: ByteString)
 -- performs initialization and creates a WAI application. This is also the
 -- place to put your migrate statements to have automatic database
 -- migrations handled by Yesod.
-with~sitearg~ :: AppConfig -> Logger -> (Application -> IO a) -> IO ()
+with~sitearg~ :: AppConfig DefaultEnv -> Logger -> (Application -> IO a) -> IO ()
 with~sitearg~ conf logger f = do
     s <- static Settings.staticDir
     Settings.withConnectionPool conf $ \p -> do~runMigration~
diff --git a/yesod/scaffold/Foundation.hs.cg b/yesod/scaffold/Foundation.hs.cg
index a925401f..6910cd26 100644
--- a/yesod/scaffold/Foundation.hs.cg
+++ b/yesod/scaffold/Foundation.hs.cg
@@ -22,6 +22,7 @@ import Settings.StaticFiles
 import Yesod.Auth
 import Yesod.Auth.OpenId
 import Yesod.Auth.Email
+import Yesod.Default.Config
 import Yesod.Logger (Logger, logLazyText)
 import qualified Settings
 import System.Directory
@@ -45,7 +46,7 @@ import Text.Shakespeare.Text (stext)
 -- starts running, such as database connections. Every handler will have
 -- access to the data present here.
 data ~sitearg~ = ~sitearg~
-    { settings :: AppConfig
+    { settings :: AppConfig DefaultEnv
     , getLogger :: Logger
     , getStatic :: Static -- ^ Settings for static file serving.
     , connPool :: Settings.ConnectionPool -- ^ Database connection pool.
diff --git a/yesod/scaffold/Settings.hs.cg b/yesod/scaffold/Settings.hs.cg
index 36bd1576..c60fb3f6 100644
--- a/yesod/scaffold/Settings.hs.cg
+++ b/yesod/scaffold/Settings.hs.cg
@@ -29,7 +29,7 @@ import Text.Shakespeare.Text (st)
 import Language.Haskell.TH.Syntax
 import Database.Persist.~importPersist~
 import Yesod (liftIO, MonadControlIO, addWidget, addCassius, addJulius, addLucius, whamletFile)
-import Yesod.Settings
+import Yesod.Default.Config
 import Data.Monoid (mempty)
 import System.Directory (doesFileExist)
 import Data.Text (Text)
@@ -55,7 +55,7 @@ staticDir = "static"
 -- have to make a corresponding change here.
 --
 -- To see how this value is used, see urlRenderOverride in Foundation.hs
-staticRoot :: AppConfig ->  Text
+staticRoot :: AppConfig DefaultEnv ->  Text
 staticRoot conf = [st|#{appRoot conf}/static|]
 
 
diff --git a/yesod/scaffold/config/mongoDB.yml.cg b/yesod/scaffold/config/mongoDB.yml.cg
index 60f74187..b97d7dfa 100644
--- a/yesod/scaffold/config/mongoDB.yml.cg
+++ b/yesod/scaffold/config/mongoDB.yml.cg
@@ -4,6 +4,7 @@ Default: &defaults
   host: localhost
   port: 27017
   database: ~project~
+  poolsize: 10
 
 Development:
   <<: *defaults
@@ -14,8 +15,10 @@ Test:
 
 Staging:
   database: ~project~_staging
+  poolsize: 100
   <<: *defaults
 
 Production:
   database: ~project~_production
+  poolsize: 100
   <<: *defaults
diff --git a/yesod/scaffold/config/postgresql.yml.cg b/yesod/scaffold/config/postgresql.yml.cg
index 2f60ddab..aceae393 100644
--- a/yesod/scaffold/config/postgresql.yml.cg
+++ b/yesod/scaffold/config/postgresql.yml.cg
@@ -4,6 +4,7 @@ Default: &defaults
   host: localhost
   port: 5432
   database: ~project~
+  poolsize: 10
 
 Development:
   <<: *defaults
@@ -14,7 +15,10 @@ Test:
 
 Staging:
   database: ~project~_staging
+  poolsize: 100
+  <<: *defaults
 
 Production:
   database: ~project~_production
+  poolsize: 100
   <<: *defaults
diff --git a/yesod/scaffold/config/settings.yml.cg b/yesod/scaffold/config/settings.yml.cg
index 1485242c..d6fad856 100644
--- a/yesod/scaffold/config/settings.yml.cg
+++ b/yesod/scaffold/config/settings.yml.cg
@@ -1,7 +1,6 @@
 Default: &defaults
   host: "http://localhost"
   port: 3000
-  connectionPoolSize: 10
 
 Development:
   <<: *defaults
diff --git a/yesod/scaffold/config/sqlite.yml.cg b/yesod/scaffold/config/sqlite.yml.cg
index b9f01df1..ebee1fa8 100644
--- a/yesod/scaffold/config/sqlite.yml.cg
+++ b/yesod/scaffold/config/sqlite.yml.cg
@@ -1,5 +1,6 @@
 Default: &defaults
   database: ~project~.sqlite3
+  poolsize: 10
 
 Development:
   <<: *defaults
@@ -10,8 +11,10 @@ Test:
 
 Staging:
   database: ~project~_staging.sqlite3
+  poolsize: 100
   <<: *defaults
 
 Production:
   database: ~project~_production.sqlite3
+  poolsize: 100
   <<: *defaults
diff --git a/yesod/scaffold/main.hs.cg b/yesod/scaffold/main.hs.cg
index 94f61c28..db9ccf5b 100644
--- a/yesod/scaffold/main.hs.cg
+++ b/yesod/scaffold/main.hs.cg
@@ -1,5 +1,6 @@
-import Yesod.Main (defaultMain, fromArgs)
-import Application (with~sitearg~)
+import Yesod.Default.Config (fromArgs)
+import Yesod.Default.Main   (defaultMain)
+import Application          (with~sitearg~)
 
 main :: IO ()
 main = defaultMain fromArgs with~sitearg~
diff --git a/yesod/scaffold/mongoDBConnPool.cg b/yesod/scaffold/mongoDBConnPool.cg
index 4292d22f..4269f2fa 100644
--- a/yesod/scaffold/mongoDBConnPool.cg
+++ b/yesod/scaffold/mongoDBConnPool.cg
@@ -1,8 +1,8 @@
 runConnectionPool :: MonadControlIO m => Action m a -> ConnectionPool -> m a
 runConnectionPool = runMongoDBConn (ConfirmWrites [u"j" =: True])
 
-withConnectionPool :: (MonadControlIO m, Applicative m) => AppConfig -> (ConnectionPool -> m b) -> m b
+withConnectionPool :: (MonadControlIO m, Applicative m) => AppConfig DefaultEnv -> (ConnectionPool -> m b) -> m b
 withConnectionPool conf f = do
-    (database,host) <- liftIO $ loadMongoConnParams (appEnv conf)
-    withMongoDBPool (u database) host (connectionPoolSize conf) f
+    dbConf <- liftIO $ loadMongo (appEnv conf)
+    withMongoDBPool (u $ mgDatabase dbConf) (mgHost dbConf) (mgPoolSize dbConf) f
 
diff --git a/yesod/scaffold/postgresqlConnPool.cg b/yesod/scaffold/postgresqlConnPool.cg
index e8597e4f..6619a88e 100644
--- a/yesod/scaffold/postgresqlConnPool.cg
+++ b/yesod/scaffold/postgresqlConnPool.cg
@@ -1,10 +1,10 @@
 runConnectionPool :: MonadControlIO m => SqlPersist m a -> ConnectionPool -> m a
 runConnectionPool = runSqlPool
 
-withConnectionPool :: MonadControlIO m => AppConfig -> (ConnectionPool -> m a) -> m a
+withConnectionPool :: MonadControlIO m => AppConfig DefaultEnv -> (ConnectionPool -> m a) -> m a
 withConnectionPool conf f = do
-    cs <- liftIO $ load~upper~ConnStr (appEnv conf)
-    with~upper~Pool cs (connectionPoolSize conf) f
+    dbConf <- liftIO $ load~upper~ (appEnv conf)
+    with~upper~Pool (pgConnStr dbConf) (pgPoolSize dbConf) f
 
 -- Example of making a dynamic configuration static
 -- use /return $(mkConnStr Production)/ instead of loadConnStr
diff --git a/yesod/scaffold/project.cabal.cg b/yesod/scaffold/project.cabal.cg
index 3109b5ed..28a7f889 100644
--- a/yesod/scaffold/project.cabal.cg
+++ b/yesod/scaffold/project.cabal.cg
@@ -58,6 +58,7 @@ executable         ~project~
                  , yesod-core
                  , yesod-auth
                  , yesod-static
+                 , yesod-default
                  , blaze-html
                  , yesod-form
                  , mime-mail
diff --git a/yesod/scaffold/sqliteConnPool.cg b/yesod/scaffold/sqliteConnPool.cg
index e8597e4f..56e1ae9d 100644
--- a/yesod/scaffold/sqliteConnPool.cg
+++ b/yesod/scaffold/sqliteConnPool.cg
@@ -1,10 +1,10 @@
 runConnectionPool :: MonadControlIO m => SqlPersist m a -> ConnectionPool -> m a
 runConnectionPool = runSqlPool
 
-withConnectionPool :: MonadControlIO m => AppConfig -> (ConnectionPool -> m a) -> m a
+withConnectionPool :: MonadControlIO m => AppConfig DefaultEnv -> (ConnectionPool -> m a) -> m a
 withConnectionPool conf f = do
-    cs <- liftIO $ load~upper~ConnStr (appEnv conf)
-    with~upper~Pool cs (connectionPoolSize conf) f
+    dbConf <- liftIO $ load~upper~ (appEnv conf)
+    with~upper~Pool (sqlDatabase dbConf) (sqlPoolSize dbConf) f
 
 -- Example of making a dynamic configuration static
 -- use /return $(mkConnStr Production)/ instead of loadConnStr
diff --git a/yesod/scaffold/tiny/Application.hs.cg b/yesod/scaffold/tiny/Application.hs.cg
index 77c73898..0bd1d218 100644
--- a/yesod/scaffold/tiny/Application.hs.cg
+++ b/yesod/scaffold/tiny/Application.hs.cg
@@ -11,8 +11,8 @@ module Application
 import Foundation
 import Settings
 import Yesod.Static
-import Yesod.Settings
-import Yesod.Main (defaultDevelApp)
+import Yesod.Default.Config
+import Yesod.Default.Main (defaultDevelApp)
 import Yesod.Logger (Logger)
 import Data.ByteString (ByteString)
 import Network.Wai (Application)
@@ -38,7 +38,7 @@ getRobotsR = return $ RepPlain $ toContent ("User-agent: *" :: ByteString)
 -- performs initialization and creates a WAI application. This is also the
 -- place to put your migrate statements to have automatic database
 -- migrations handled by Yesod.
-with~sitearg~ :: AppConfig -> Logger -> (Application -> IO a) -> IO a
+with~sitearg~ :: AppConfig DefaultEnv -> Logger -> (Application -> IO a) -> IO a
 with~sitearg~ conf logger f = do
 #ifdef PRODUCTION
     s <- static Settings.staticDir
diff --git a/yesod/scaffold/tiny/Foundation.hs.cg b/yesod/scaffold/tiny/Foundation.hs.cg
index 5e950805..58bb57c9 100644
--- a/yesod/scaffold/tiny/Foundation.hs.cg
+++ b/yesod/scaffold/tiny/Foundation.hs.cg
@@ -14,7 +14,7 @@ module Foundation
     ) where
 
 import Yesod.Core
-import Yesod.Settings (AppConfig(..))
+import Yesod.Default.Config
 import Yesod.Static (Static, base64md5, StaticRoute(..))
 import Settings.StaticFiles
 import Yesod.Logger (Logger, logLazyText)
@@ -33,7 +33,7 @@ import Web.ClientSession (getKey)
 -- starts running, such as database connections. Every handler will have
 -- access to the data present here.
 data ~sitearg~ = ~sitearg~
-    { settings :: AppConfig
+    { settings :: AppConfig DefaultEnv
     , getLogger :: Logger
     , getStatic :: Static -- ^ Settings for static file serving.
     }
diff --git a/yesod/scaffold/tiny/Settings.hs.cg b/yesod/scaffold/tiny/Settings.hs.cg
index a36c764b..605bc709 100644
--- a/yesod/scaffold/tiny/Settings.hs.cg
+++ b/yesod/scaffold/tiny/Settings.hs.cg
@@ -24,7 +24,7 @@ import qualified Text.Shakespeare.Text as S
 import Text.Shakespeare.Text (st)
 import Language.Haskell.TH.Syntax
 import Yesod.Widget (addWidget, addCassius, addJulius, addLucius, whamletFile)
-import Yesod.Settings
+import Yesod.Default.Config
 import Data.Monoid (mempty)
 import System.Directory (doesFileExist)
 import Data.Text (Text)
@@ -47,7 +47,7 @@ staticDir = "static"
 -- have to make a corresponding change here.
 --
 -- To see how this value is used, see urlRenderOverride in ~project~.hs
-staticRoot :: AppConfig ->  Text
+staticRoot :: AppConfig DefaultEnv ->  Text
 staticRoot conf = [st|#{appRoot conf}/static|]
 
 -- The rest of this file contains settings which rarely need changing by a
diff --git a/yesod/scaffold/tiny/project.cabal.cg b/yesod/scaffold/tiny/project.cabal.cg
index 6e5c3cc5..1cc7fb75 100644
--- a/yesod/scaffold/tiny/project.cabal.cg
+++ b/yesod/scaffold/tiny/project.cabal.cg
@@ -46,9 +46,9 @@ executable         ~project~
     hs-source-dirs: .
 
     build-depends: base         >= 4       && < 5
-                 , yesod        >= 0.9     && < 0.10
                  , yesod-core   >= 0.9     && < 0.10
                  , yesod-static
+                 , yesod-default
                  , clientsession
                  , wai-extra
                  , directory