diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,22 @@
+Copyright (c) 2015, Sannsyn AS
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
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/aeson-value-parser.cabal b/aeson-value-parser.cabal
new file mode 100644
--- /dev/null
+++ b/aeson-value-parser.cabal
@@ -0,0 +1,56 @@
+name:
+  aeson-value-parser
+version:
+  0.9.0
+synopsis:
+  An API for parsing "aeson" JSON tree into Haskell types
+description:
+category:
+  Data, JSON, Parsing
+homepage:
+  https://github.com/sannsyn/aeson-value-parser 
+bug-reports:
+  https://github.com/sannsyn/aeson-value-parser/issues 
+author:
+  Nikita Volkov <nikita.y.volkov@mail.ru>
+maintainer:
+  Nikita Volkov <nikita.y.volkov@mail.ru>
+copyright:
+  (c) 2015, Sannsyn AS
+license:
+  MIT
+license-file:
+  LICENSE
+build-type:
+  Simple
+cabal-version:
+  >=1.10
+
+
+source-repository head
+  type:
+    git
+  location:
+    git://github.com/sannsyn/aeson-value-parser.git
+
+
+library
+  hs-source-dirs:
+    library
+  default-extensions:
+    Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFunctor, DeriveGeneric, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, ImpredicativeTypes, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples
+  default-language:
+    Haskell2010
+  other-modules:
+  exposed-modules:
+    Aeson.ValueParser
+  build-depends:
+    --
+    aeson >= 0.8 && < 0.10,
+    unordered-containers == 0.2.*,
+    vector >= 0.10 && < 0.12,
+    scientific == 0.3.*,
+    text == 1.*,
+    --
+    mtl-prelude < 3,
+    base-prelude >= 0.1.19 && < 0.2
diff --git a/library/Aeson/ValueParser.hs b/library/Aeson/ValueParser.hs
new file mode 100644
--- /dev/null
+++ b/library/Aeson/ValueParser.hs
@@ -0,0 +1,144 @@
+module Aeson.ValueParser
+(
+  ValueParser,
+  ArrayParser,
+  ObjectParser,
+  run,
+  -- * Value parsers
+  onArray,
+  onObject,
+  onNullable,
+  string,
+  number,
+  bool,
+  fromJSON,
+  -- * Object parsers
+  onKey,
+  onAllKeys,
+  -- * Array parsers
+  onIndex,
+  onAllIndexes,
+)
+where
+
+import BasePrelude hiding (bool)
+import MTLPrelude
+import Data.Text (Text)
+import Data.Scientific (Scientific)
+import qualified Data.Aeson as A
+import qualified Data.HashMap.Strict as B
+import qualified Data.Vector as C
+
+
+newtype Result a =
+  Result { resultEither :: Either Text a }
+  deriving (Functor, Applicative, Monad, MonadError Text)
+
+instance Alternative Result where
+  empty = 
+    Result $ Left "No result"
+  (<|>) =
+    \case
+      Result (Left _) -> id
+      r -> const r
+
+instance MonadPlus Result where
+  mzero = empty
+  mplus = (<|>)
+
+
+type ValueParser =
+  ReaderT A.Value Result
+
+type ArrayParser =
+  ReaderT A.Array Result
+
+type ObjectParser =
+  ReaderT A.Object Result
+
+run :: ValueParser a -> A.Value -> Either Text a
+run effect =
+  resultEither . runReaderT effect
+
+-- * Value parsers
+-------------------------
+
+onArray :: ArrayParser a -> ValueParser a
+onArray effect =
+  ReaderT $ \case
+    A.Array x ->
+      runReaderT effect x
+    _ ->
+      Result $ Left "Not an array"
+
+onObject :: ObjectParser a -> ValueParser a
+onObject effect =
+  ReaderT $ \case
+    A.Object x ->
+      runReaderT effect x
+    _ ->
+      Result $ Left "Not an object"
+
+onNullable :: ValueParser a -> ValueParser (Maybe a)
+onNullable q =
+  ReaderT $ \case
+    A.Null ->
+      return Nothing
+    x -> 
+      Result $ fmap Just $ run q x
+
+string :: ValueParser Text
+string =
+  ReaderT $ \case
+    A.String t ->
+      return t
+    _ ->
+      Result $ Left "Not a string"
+
+number :: ValueParser Scientific
+number =
+  ReaderT $ \case
+    A.Number x ->
+      return x
+    _ ->
+      Result $ Left "Not a number"
+
+bool :: ValueParser Bool
+bool =
+  ReaderT $ \case
+    A.Bool x -> 
+      return x
+    _ -> 
+      Result $ Left "Not a bool"
+
+fromJSON :: A.FromJSON a => ValueParser a
+fromJSON =
+  ReaderT $ A.fromJSON >>> \case
+    A.Error m -> Result $ Left $ fromString m
+    A.Success r -> Result $ Right $ r
+
+-- * Object parsers
+-------------------------
+
+onKey :: Text -> ValueParser a -> ObjectParser a
+onKey key effect =
+  ReaderT $
+    maybe (Result $ Left $ "Object contains no field '" <> key <> "'") (runReaderT effect) .
+    B.lookup key
+
+onAllKeys :: ValueParser a -> ObjectParser (B.HashMap Text a)
+onAllKeys effect =
+  ReaderT $ mapM (runReaderT effect)
+
+-- * Array parsers
+-------------------------
+
+onIndex :: Int -> ValueParser a -> ArrayParser a
+onIndex index effect =
+  ReaderT $ 
+    maybe (Result $ Left $ "Array has no index '" <> (fromString . show) index <> "'") (runReaderT effect) .
+    flip (C.!?) index
+
+onAllIndexes :: ValueParser a -> ArrayParser (C.Vector a)
+onAllIndexes effect =
+  ReaderT $ mapM (runReaderT effect)