diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Changelog for yaml-pretty-extras
 
+## v0.0.2.1
+
+Add lens helpers, transformFile, overFile, traverseOfFile, sanitizeFile
+
 ## v0.0.2.0
 
 Add haddock documentation.
diff --git a/src/Data/Yaml/Pretty/Extras.hs b/src/Data/Yaml/Pretty/Extras.hs
--- a/src/Data/Yaml/Pretty/Extras.hs
+++ b/src/Data/Yaml/Pretty/Extras.hs
@@ -23,12 +23,22 @@
   , displayPrettyYaml
   , decodeFileThrowLogged
   , encodeFilePrettyLogged
+
+  -- Transformers and Lenses
+
+  , transformFile
+  , inplace
+  , sanitizeFile
+  , overFile
+  , traverseOfFile
+
   )
 where
 
 import           Data.Typeable
 import           Data.Yaml
 import           Data.Yaml.Pretty
+import           Lens.Micro.Platform
 import           RIO
 import qualified RIO.ByteString                as BS
 import           RIO.List
@@ -119,3 +129,43 @@
     ]
   encodeFilePretty x d
   logInfo $ "Saved " <> displayShow x
+
+-- | Run a function over a decoded file f and save the result to g, passthrough the new value.
+
+transformFile
+  :: (MonadIO m, FromJSON a1, MonadThrow m, ToPrettyYaml a2) =>
+      FilePath -> FilePath -> (a1 -> a2) -> m a2
+transformFile f g l = do
+  (x :: a1) <- decodeFileThrow f
+  encodeFilePretty g (l x)
+  return (l x)
+
+-- | Performs a file operation in place
+
+inplace :: (FilePath -> FilePath -> a) -> FilePath -> a
+inplace = join
+
+-- | Perform a roundtrip decode/encode on a file to rearrange field order. Doesn't change the type.
+
+sanitizeFile
+  :: (MonadIO m, FromJSON a, MonadThrow m, ToPrettyYaml a) =>
+     FilePath -> m a
+sanitizeFile = flip (inplace transformFile) id
+
+-- | Uses a lens over to modify a file, passthrough the new value.
+
+overFile
+  :: (MonadIO m, FromJSON a1, MonadThrow m, ToPrettyYaml a2) =>
+     FilePath -> FilePath -> ASetter a1 a2 a b -> (a -> b) -> m a2
+overFile f g l a = transformFile f g (over l a)
+
+-- | Use a lens traverseOf to modify a file, passthrough the new value.
+
+traverseOfFile
+  :: (MonadIO m, FromJSON a1, MonadThrow m, ToPrettyYaml a2) =>
+     FilePath -> FilePath -> LensLike m a1 a2 b1 b2 -> (b1 -> m b2) -> m a2
+traverseOfFile f g l a = do
+  (x :: a1) <- decodeFileThrow f
+  y <- traverseOf l a x
+  encodeFilePretty g y
+  return y
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -1,21 +1,44 @@
-{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE TemplateHaskell #-}
+
 import           Data.Yaml.Pretty.Extras
 import           GHC.Generics
+import           Lens.Micro.Platform hiding ((.=))
 import           RIO
 import qualified RIO.ByteString                as BS
 import           Test.Hspec
 
 
 data Person = Person {
-  mood :: Text,
-  job  :: Text
-} deriving (Eq, Generic, FromJSON, Show, ToJSON)
+  _mood :: Text,
+  _job  :: Text
+} deriving (Eq, Generic, Show)
 
+instance FromJSON Person where
+  parseJSON (Object v) = Person
+    <$> v .: "mood"
+    <*> v .: "job"
+
+instance ToJSON Person where
+  toJSON x = object ["mood" .= _mood x, "job" .= _job x]
+
+$(makeLenses ''Person)
+
 data Conf = Conf {
-  name :: Text,
-  kind :: Text,
-  people :: [Person]
-} deriving (Eq, Generic, FromJSON, Show, ToJSON)
+  _name :: Text,
+  _kind :: Text,
+  _people :: [Person]
+} deriving (Eq, Generic, Show)
+
+instance FromJSON Conf where
+  parseJSON (Object v) = Conf
+    <$> v .: "name"
+    <*> v .: "kind"
+    <*> v .: "people"
+
+instance ToJSON Conf where
+  toJSON x = object ["name" .= _name x, "kind" .= _kind x, "people" .= _people x]
+
+$(makeLenses ''Conf)
 
 instance ToPrettyYaml Conf where
   fieldOrder = const ["name", "kind", "people", "mood", "job"]
diff --git a/yaml-pretty-extras.cabal b/yaml-pretty-extras.cabal
--- a/yaml-pretty-extras.cabal
+++ b/yaml-pretty-extras.cabal
@@ -2,10 +2,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 010d745442891bcf2faf89ea29834fe82716bfc1ab9555e945b01d2990a228d6
+-- hash: 30a719434a8c574644339e466446c2756dcb9b3b71213d82bd7a55dc77c157c1
 
 name:           yaml-pretty-extras
-version:        0.0.2.0
+version:        0.0.2.1
 synopsis:       Extra functionality for pretty printing Yaml documents.
 description:    Extra functionality for pretty printing Yaml documents. Allows precise field ordering.
 category:       Data
@@ -34,6 +34,7 @@
   default-extensions: AutoDeriveTypeable BangPatterns BinaryLiterals ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable DoAndIfThenElse EmptyDataDecls ExistentialQuantification FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase MonadFailDesugaring MultiParamTypeClasses MultiWayIf NamedFieldPuns NoImplicitPrelude OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving TupleSections TypeFamilies TypeSynonymInstances ViewPatterns
   build-depends:
       base >=4.7 && <5
+    , microlens-platform
     , rio
     , yaml
   default-language: Haskell2010
@@ -50,6 +51,7 @@
   build-depends:
       base >=4.7 && <5
     , hspec
+    , microlens-platform
     , rio
     , yaml
     , yaml-pretty-extras