diff --git a/MODULE.md b/MODULE.md
index 6bbdf29..1ef75ff 100644
--- a/MODULE.md
+++ b/MODULE.md
@@ -37,7 +37,7 @@ type ConnectionInfo = { password :: String, user :: String, port :: Number, db :
 connect :: forall eff. ConnectionInfo -> Aff (db :: DB | eff) Client
 ```
 
-Makes a connection to the database
+Makes a connection to the database.
 
 #### `execute`
 
@@ -45,7 +45,7 @@ Makes a connection to the database
 execute :: forall eff a. Query a -> [SqlValue] -> Client -> Aff (db :: DB | eff) Unit
 ```
 
-Runs a query and returns nothing
+Runs a query and returns nothing.
 
 #### `execute_`
 
@@ -61,7 +61,7 @@ Runs a query and returns nothing
 query :: forall eff a p. (IsForeign a) => Query a -> [SqlValue] -> Client -> Aff (db :: DB | eff) [F a]
 ```
 
-Runs a query and returns all results
+Runs a query and returns all results.
 
 #### `query_`
 
@@ -93,7 +93,7 @@ Just like `queryOne` but does not make any param replacement
 queryValue :: forall eff a. (IsForeign a) => Query a -> [SqlValue] -> Client -> Aff (db :: DB | eff) (Maybe a)
 ```
 
-Runs a query and returns a single value, if any
+Runs a query and returns a single value, if any.
 
 #### `queryValue_`
 
@@ -112,6 +112,16 @@ withConnection :: forall eff a. ConnectionInfo -> (Client -> Aff (db :: DB | eff
 Connects to the database, calls the provided function with the client
 and returns the results.
 
+#### `end`
+
+``` purescript
+end :: forall eff. Client -> Eff (db :: DB | eff) Unit
+```
+
+
+
+## Module Database.Postgres.SqlValue
+
 #### `SqlValue`
 
 ``` purescript
@@ -148,10 +158,10 @@ instance isSqlValueInt :: IsSqlValue Int
 ```
 
 
-#### `end`
+#### `isSqlValueMaybe`
 
 ``` purescript
-end :: forall eff. Client -> Eff (db :: DB | eff) Unit
+instance isSqlValueMaybe :: (IsSqlValue a) => IsSqlValue (Maybe a)
 ```
 
 
diff --git a/src/Database/Postgres.purs b/src/Database/Postgres.purs
index 68aa2e1..e7a1ffb 100644
--- a/src/Database/Postgres.purs
+++ b/src/Database/Postgres.purs
@@ -3,9 +3,6 @@ module Database.Postgres
   , Client()
   , DB()
   , ConnectionInfo()
-  , SqlValue()
-  , IsSqlValue
-  , toSql
   , connect
   , end
   , execute, execute_
@@ -23,13 +20,14 @@ import Data.Array
 import Data.Foreign
 import Data.Foreign.Class
 import Data.Maybe
-import Data.Int
 import Control.Monad.Aff
 import Control.Monad.Eff.Class
 import Control.Monad.Eff.Exception(Error(), error)
 import Control.Monad.Error.Class (throwError)
 import Data.Traversable (sequence)
 
+import Database.Postgres.SqlValue
+
 newtype Query a = Query String
 
 foreign import data Client :: *
@@ -123,26 +121,6 @@ finally a sequel = do
   sequel
   either throwError pure res
 
-foreign import data SqlValue :: *
-
-foreign import unsafeToSqlValue """
-  function unsafeToSqlValue(x) {
-    return x;
-  }
-  """ :: forall a. a -> SqlValue
-
-class IsSqlValue a where
-  toSql :: a -> SqlValue
-
-instance isSqlValueString :: IsSqlValue String where
-  toSql = unsafeToSqlValue
-
-instance isSqlValueNumber :: IsSqlValue Number where
-  toSql = unsafeToSqlValue
-
-instance isSqlValueInt :: IsSqlValue Int where
-  toSql = unsafeToSqlValue <<< toNumber
-
 
 foreign import connect' """
   function connect$prime(conString) {
diff --git a/src/Database/Postgres/SqlValue.purs b/src/Database/Postgres/SqlValue.purs
new file mode 100644
index 0000000..4dc6757
--- /dev/null
+++ b/src/Database/Postgres/SqlValue.purs
@@ -0,0 +1,34 @@
+module Database.Postgres.SqlValue
+  ( SqlValue()
+  , IsSqlValue
+  , toSql
+  ) where
+
+import Data.Int
+import Data.Maybe
+
+foreign import data SqlValue :: *
+
+class IsSqlValue a where
+  toSql :: a -> SqlValue
+
+instance isSqlValueString :: IsSqlValue String where
+  toSql = unsafeToSqlValue
+
+instance isSqlValueNumber :: IsSqlValue Number where
+  toSql = unsafeToSqlValue
+
+instance isSqlValueInt :: IsSqlValue Int where
+  toSql = unsafeToSqlValue <<< toNumber
+
+instance isSqlValueMaybe :: (IsSqlValue a) => IsSqlValue (Maybe a) where
+  toSql Nothing = nullSqlValue
+  toSql (Just x) = toSql x
+
+foreign import unsafeToSqlValue """
+  function unsafeToSqlValue(x) {
+    return x;
+  }
+  """ :: forall a. a -> SqlValue
+
+foreign import nullSqlValue "var nullSqlValue = null;" :: SqlValue
diff --git a/test/Main.purs b/test/Main.purs
index 7024ce3..e3f03b1 100644
--- a/test/Main.purs
+++ b/test/Main.purs
@@ -1,6 +1,7 @@
 module Test.Main where
 
 import Database.Postgres
+import Database.Postgres.SqlValue
 import Debug.Trace
 import Control.Monad.Eff
 import Control.Monad.Eff.Class