diff --git a/src/YamlParse/Applicative.hs b/src/YamlParse/Applicative.hs
--- a/src/YamlParse/Applicative.hs
+++ b/src/YamlParse/Applicative.hs
@@ -102,6 +102,7 @@
     YamlParser,
     ObjectParser,
     Parser (..),
+    FieldParser (..),
 
     -- * Using a yaml schema
 
diff --git a/src/YamlParse/Applicative/Explain.hs b/src/YamlParse/Applicative/Explain.hs
--- a/src/YamlParse/Applicative/Explain.hs
+++ b/src/YamlParse/Applicative/Explain.hs
@@ -28,7 +28,11 @@
   | StringSchema (Maybe Text)
   | ArraySchema (Maybe Text) Schema
   | ObjectSchema (Maybe Text) Schema
-  | FieldSchema Text Bool (Maybe Text) Schema
+  | FieldSchema
+      Text -- Field name
+      Bool -- Required
+      (Maybe Text) -- Default value
+      Schema -- Schema of the value
   | ListSchema Schema
   | MapSchema Schema
   | MapKeysSchema Schema
@@ -60,11 +64,10 @@
       ParseArray t p -> ArraySchema t $ go p
       ParseObject t p -> ObjectSchema t $ go p
       ParseField k fp -> case fp of
+        FieldParserFmap _ fp' -> go $ ParseField k fp'
         FieldParserRequired p -> FieldSchema k True Nothing $ go p
         FieldParserOptional p -> FieldSchema k False Nothing $ go p
         FieldParserOptionalWithDefault p d -> FieldSchema k False (Just $ T.pack $ show d) $ go p
-        FieldParserOptionalOrNull p -> FieldSchema k False Nothing $ go p
-        FieldParserOptionalOrNullWithDefault p d -> FieldSchema k False (Just $ T.pack $ show d) $ go p
       ParseList p -> ListSchema $ go p
       ParseMap p -> MapSchema $ go p
       ParseMapKeys _ p -> MapKeysSchema $ go p
diff --git a/src/YamlParse/Applicative/Implement.hs b/src/YamlParse/Applicative/Implement.hs
--- a/src/YamlParse/Applicative/Implement.hs
+++ b/src/YamlParse/Applicative/Implement.hs
@@ -63,25 +63,16 @@
           Yaml.Object o -> go p o
           _ -> Aeson.typeMismatch "Object" v
       ParseField key fp -> \o -> case fp of
+        FieldParserFmap f fp' -> f <$> go (ParseField key fp') o
         FieldParserRequired p -> do
           v <- o Yaml..: key
           go p v
-        FieldParserOptional p ->
+        FieldParserOptional p -> do
           case HM.lookup key o of
             Nothing -> pure Nothing
             Just v -> Just <$> go p v
-        FieldParserOptionalWithDefault p d ->
+        FieldParserOptionalWithDefault p d -> do
           case HM.lookup key o of
-            Nothing -> pure d
-            Just v -> go p v
-        FieldParserOptionalOrNull p -> do
-          mv <- o Yaml..:? key
-          case mv of
-            Nothing -> pure Nothing
-            Just v -> Just <$> go p v
-        FieldParserOptionalOrNullWithDefault p d -> do
-          mv <- o Yaml..:? key
-          case mv of
             Nothing -> pure d
             Just v -> go p v
       ParseList p -> mapM (go p)
diff --git a/src/YamlParse/Applicative/Parser.hs b/src/YamlParse/Applicative/Parser.hs
--- a/src/YamlParse/Applicative/Parser.hs
+++ b/src/YamlParse/Applicative/Parser.hs
@@ -6,6 +6,7 @@
 module YamlParse.Applicative.Parser where
 
 import Control.Applicative
+import Control.Monad
 import qualified Data.Aeson as JSON
 import qualified Data.ByteString.Lazy as LB
 import Data.HashMap.Strict (HashMap)
@@ -117,12 +118,14 @@
   many = undefined
 
 data FieldParser o where
+  FieldParserFmap :: (a -> b) -> FieldParser a -> FieldParser b
   FieldParserRequired :: YamlParser o -> FieldParser o
   FieldParserOptional :: YamlParser o -> FieldParser (Maybe o)
   FieldParserOptionalWithDefault :: Show o => YamlParser o -> o -> FieldParser o
-  FieldParserOptionalOrNull :: YamlParser o -> FieldParser (Maybe o)
-  FieldParserOptionalOrNullWithDefault :: Show o => YamlParser o -> o -> FieldParser o
 
+instance Functor FieldParser where
+  fmap = FieldParserFmap
+
 type YamlParser a = Parser Yaml.Value a
 
 type ObjectParser a = Parser Yaml.Object a
@@ -255,23 +258,23 @@
 
 -- | A parser for an optional field at a given key with a parser for what is found at that key
 optionalFieldWith :: Text -> Text -> YamlParser a -> ObjectParser (Maybe a)
-optionalFieldWith k h func = ParseComment h $ ParseField k $ FieldParserOptionalOrNull func
+optionalFieldWith k h func = ParseComment h $ ParseField k $ fmap join $ FieldParserOptional $ ParseMaybe func
 
 -- | A parser for an optional field at a given key with a parser for what is found at that key without a help text
 optionalFieldWith' :: Text -> YamlParser a -> ObjectParser (Maybe a)
-optionalFieldWith' k func = ParseField k $ FieldParserOptionalOrNull func
+optionalFieldWith' k func = ParseField k $ fmap join $ FieldParserOptional $ ParseMaybe func
 
 -- | A parser for an optional field at a given key with a default value and a parser for what is found at that key
 --
 -- For the sake of documentation, the default value needs to be showable.
 optionalFieldWithDefaultWith :: Show a => Text -> a -> Text -> YamlParser a -> ObjectParser a
-optionalFieldWithDefaultWith k d h func = ParseComment h $ ParseField k $ FieldParserOptionalOrNullWithDefault func d
+optionalFieldWithDefaultWith k d h func = ParseComment h $ ParseField k $ FieldParserOptionalWithDefault func d
 
 -- | A parser for an optional field at a given key with a default value and a parser for what is found at that key without a help text
 --
 -- For the sake of documentation, the default value needs to be showable.
 optionalFieldWithDefaultWith' :: Show a => Text -> a -> YamlParser a -> ObjectParser a
-optionalFieldWithDefaultWith' k d func = ParseField k $ FieldParserOptionalOrNullWithDefault func d
+optionalFieldWithDefaultWith' k d func = ParseField k $ FieldParserOptionalWithDefault func d
 
 -- | Make a parser that parses a value using the given extra parsing function
 --
diff --git a/src/YamlParse/Applicative/Pretty.hs b/src/YamlParse/Applicative/Pretty.hs
--- a/src/YamlParse/Applicative/Pretty.hs
+++ b/src/YamlParse/Applicative/Pretty.hs
@@ -120,7 +120,7 @@
             AnySchema -> e "<any>" cs
             ExactSchema t -> e (pretty t) cs <+> fromJust (mkCommentsMDoc $ comment "(exact)")
             NullSchema -> e "null" cs
-            MaybeSchema s -> go (cs <> comment "or <null>") s
+            MaybeSchema s -> go (comment "or <null>" <> cs) s
             BoolSchema t -> e "<boolean>" $ addMComment cs t
             NumberSchema t -> e "<number>" $ addMComment cs t
             StringSchema t -> e "<string>" $ addMComment cs t
diff --git a/yamlparse-applicative.cabal b/yamlparse-applicative.cabal
--- a/yamlparse-applicative.cabal
+++ b/yamlparse-applicative.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           yamlparse-applicative
-version:        0.1.0.4
+version:        0.2.0.0
 synopsis:       Declaritive configuration parsing with free docs
 description:    See https://github.com/NorfairKing/yamlparse-applicative
 homepage:       https://github.com/NorfairKing/yamlparse-applicative#readme