diff --git a/Data/Double/Extra.hs b/Data/Double/Extra.hs
new file mode 100644
--- /dev/null
+++ b/Data/Double/Extra.hs
@@ -0,0 +1,15 @@
+{-# LANGUAGE CPP #-}
+module Data.Double.Extra
+ ( module X
+ ) where
+
+import Data.Double.Extra.Types as X
+import Data.Double.Extra.Aeson as X
+
+#if CASSAVA
+import Data.Double.Extra.Cassava as X
+#endif
+
+#if RAWSTRING_QM
+import Data.Double.Extra.RawString as X
+#endif
diff --git a/Data/Double/Extra/Aeson.hs b/Data/Double/Extra/Aeson.hs
new file mode 100644
--- /dev/null
+++ b/Data/Double/Extra/Aeson.hs
@@ -0,0 +1,31 @@
+module Data.Double.Extra.Aeson where
+
+import Data.Double.Extra.Types
+import qualified Data.ByteString.Builder as B
+import Data.Aeson (FromJSON(..), ToJSON(..))
+import qualified Data.Aeson.Types as AI
+import Data.Double.Conversion.ByteString
+
+instance FromJSON (DoubleFixed n) where
+  parseJSON = coerce . (parseJSON :: AI.Value -> AI.Parser Double)
+instance KnownNat n => ToJSON (DoubleFixed n) where
+ toJSON = (toJSON :: Double -> AI.Value) . coerce
+ toEncoding x = AI.unsafeToEncoding $  B.byteString . toFixed (fromIntegral (natVal x)) $ coerce x
+
+instance FromJSON (DoublePrecision n) where
+  parseJSON = coerce . (parseJSON :: AI.Value -> AI.Parser Double)
+instance KnownNat n => ToJSON (DoublePrecision n) where
+ toJSON = (toJSON :: Double -> AI.Value) . coerce
+ toEncoding x = AI.unsafeToEncoding $  B.byteString . toPrecision (fromIntegral (natVal x)) $ coerce x
+
+instance FromJSON (DoubleExponential n) where
+  parseJSON = coerce . (parseJSON :: AI.Value -> AI.Parser Double)
+instance KnownNat n => ToJSON (DoubleExponential n) where
+ toJSON = (toJSON :: Double -> AI.Value) . coerce
+ toEncoding x = AI.unsafeToEncoding $  B.byteString . toExponential (fromIntegral (natVal x)) $ coerce x
+
+instance FromJSON DoubleShortest where
+  parseJSON = coerce . (parseJSON :: AI.Value -> AI.Parser Double)
+instance ToJSON DoubleShortest where
+ toJSON = (toJSON :: Double -> AI.Value) . coerce
+ toEncoding = AI.unsafeToEncoding . B.byteString . toShortest . coerce
diff --git a/Data/Double/Extra/Cassava.hs b/Data/Double/Extra/Cassava.hs
new file mode 100644
--- /dev/null
+++ b/Data/Double/Extra/Cassava.hs
@@ -0,0 +1,17 @@
+module Data.Double.Extra.Cassava where
+
+import Data.Double.Extra.Types
+import Data.Double.Conversion.ByteString
+import qualified Data.Csv as CSV
+
+instance KnownNat n => CSV.ToField (DoubleFixed n) where
+  toField x = toFixed (fromIntegral (natVal x)) $ coerce x
+
+instance KnownNat n => CSV.ToField (DoublePrecision n) where
+  toField x = toPrecision (fromIntegral (natVal x)) $ coerce x
+
+instance KnownNat n => CSV.ToField (DoubleExponential n) where
+  toField x = toExponential (fromIntegral (natVal x)) $ coerce x
+
+instance CSV.ToField DoubleShortest where
+  toField = coerce toShortest
diff --git a/Data/Double/Extra/RawString.hs b/Data/Double/Extra/RawString.hs
new file mode 100644
--- /dev/null
+++ b/Data/Double/Extra/RawString.hs
@@ -0,0 +1,31 @@
+module Data.Double.Extra.RawString where
+
+import Data.Text.ToText
+import Data.Text.ToTextBuilder
+import Data.Double.Extra.Types
+import Data.Double.Conversion.Text
+import Data.Text.Lazy.Builder as B
+import qualified Data.Text.Lazy as TL
+
+instance KnownNat n => ToTextBuilder (DoubleFixed n) where
+  toTextBuilder x = B.fromText . toFixed (fromIntegral (natVal x)) $ coerce x
+instance KnownNat n => ToTextBuilder (DoublePrecision n) where
+  toTextBuilder x = B.fromText . toPrecision (fromIntegral (natVal x)) $ coerce x
+instance KnownNat n => ToTextBuilder (DoubleExponential n) where
+  toTextBuilder x = B.fromText . toExponential (fromIntegral (natVal x)) $ coerce x
+instance ToTextBuilder DoubleShortest where
+  toTextBuilder = B.fromText . toShortest . coerce
+
+
+instance KnownNat n => ToText (DoubleFixed n) where
+  toText x = toFixed (fromIntegral (natVal x)) $ coerce x
+  toLazyText = TL.fromStrict . toText
+instance KnownNat n => ToText (DoublePrecision n) where
+  toText x = toPrecision (fromIntegral (natVal x)) $ coerce x
+  toLazyText = TL.fromStrict . toText
+instance KnownNat n => ToText (DoubleExponential n) where
+  toText x = toExponential (fromIntegral (natVal x)) $ coerce x
+  toLazyText = TL.fromStrict . toText
+instance ToText DoubleShortest where
+  toText = toShortest . coerce
+  toLazyText = TL.fromStrict . toText
diff --git a/Data/Double/Extra/Types.hs b/Data/Double/Extra/Types.hs
new file mode 100644
--- /dev/null
+++ b/Data/Double/Extra/Types.hs
@@ -0,0 +1,31 @@
+module Data.Double.Extra.Types
+ ( DoublePrecision(..)
+ , DoubleExponential(..)
+ , DoubleFixed(..)
+ , DoubleShortest(..)
+ , module X
+ ) where
+
+import Control.DeepSeq (NFData)
+import GHC.TypeLits as X
+import Data.Coerce as X
+import GHC.Generics
+
+newtype DoublePrecision (i :: Nat) = DoublePrecision Double
+  deriving (Eq,Ord,Show,Read,Generic,NFData,Num)
+
+newtype DoubleExponential (i :: Nat) = DoubleExponential Double
+  deriving (Eq,Ord,Show,Read,Generic,NFData,Num)
+
+newtype DoubleFixed (i :: Nat) = DoubleFixed Double
+  deriving (Eq,Ord,Show,Read,Generic,NFData,Num)
+
+newtype DoubleShortest = DoubleShortest Double
+  deriving (Eq,Ord,Show,Read,Generic,NFData,Num)
+
+{-
+DoublePrecision (i :: Nat)
+DoubleExponential (i :: Nat)
+DoubleFixed (i :: Nat)
+DoubleShortest
+-}
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Marcin Tolysz (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Marcin Tolysz nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# double-extra
+Missing presentations for Double numbers (fixed, scientific etc.)
+
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/double-extra.cabal b/double-extra.cabal
new file mode 100644
--- /dev/null
+++ b/double-extra.cabal
@@ -0,0 +1,55 @@
+name:                double-extra
+version:             0.1.0.0
+synopsis:            Missing presentations for Double numbers (fixed, scientific etc.)
+description:         Please see README.md
+homepage:            https://github.com/tolysz/double-extra#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Marcin Tolysz
+maintainer:          tolysz@gmail.com
+copyright:           2017(c) Marcin Tolysz
+category:            Library
+build-type:          Simple
+extra-source-files:  README.md
+cabal-version:       >=1.10
+
+Flag cassava
+  Description: Build the example server
+  Default:     True
+
+Flag rawstring-qm
+  Description: Build the example server
+  Default:     True
+
+library
+  exposed-modules:
+           Data.Double.Extra
+  other-modules:
+           Data.Double.Extra.Aeson
+           Data.Double.Extra.Types
+
+  build-depends:  base >= 4.7 && < 5
+               ,  double-conversion == 2.0.2.0
+               ,  aeson
+               ,  bytestring
+               ,  deepseq
+  if flag(cassava)
+     build-depends: cassava
+     other-modules: Data.Double.Extra.Cassava
+     cpp-options: -DCASSAVA
+
+  if flag(rawstring-qm)
+     build-depends: rawstring-qm, text
+     other-modules: Data.Double.Extra.RawString
+     cpp-options: -DRAWSTRING_QM
+
+  default-language:    Haskell2010
+  default-extensions:
+    KindSignatures
+    DataKinds
+    DeriveGeneric
+    GeneralizedNewtypeDeriving
+
+source-repository head
+  type:     git
+  location: https://github.com/tolysz/double-extra