diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2016 Kadzuya OKAMOTO
+
+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/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,9 @@
+[![test](https://github.com/arowM/type-level-kv-list/actions/workflows/test.yaml/badge.svg)](https://github.com/arowM/type-level-kv-list/actions/workflows/test.yaml)
+[![Hackage](https://img.shields.io/hackage/v/type-level-kv-list.svg)](https://hackage.haskell.org/package/type-level-kv-list)
+[![Stackage LTS](http://stackage.org/package/type-level-kv-list/badge/lts)](http://stackage.org/lts/package/type-level-kv-list)
+[![Stackage Nightly](http://stackage.org/package/type-level-kv-list/badge/nightly)](http://stackage.org/nightly/package/type-level-kv-list)
+
+# type-level-kv-list
+
+This library provides a brief implementation for extensible records.
+It is sensitive to the ordering of key-value items, but has simple type constraints and provides short compile time.
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/src/Data/KVList.hs b/src/Data/KVList.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/KVList.hs
@@ -0,0 +1,133 @@
+{-| This library provide a brief implementation for extensible records.
+  It is sensitive to the ordering of key-value items, but has simple type constraints and provides short compile time.
+-}
+
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+module Data.KVList
+  (
+  -- * Constructors
+  -- $setup
+    KVList
+  , (:=)((:=))
+  , (&=)
+  , kvcons
+  , empty
+  , singleton
+  , ListKey(..)
+
+  -- * Operators
+  , get
+  , HasKey
+  , (&.)
+  )
+where
+
+import Prelude
+
+import Data.Kind (Constraint, Type)
+import Data.Typeable (Typeable, typeOf)
+import GHC.TypeLits (KnownSymbol, Symbol, TypeError, ErrorMessage(Text))
+import GHC.OverloadedLabels (IsLabel(..))
+import Unsafe.Coerce (unsafeCoerce)
+
+
+-- Constructors
+
+{- $setup #constructors#
+  We can create type level KV list as follows.
+
+  >>> :set -XOverloadedLabels -XTypeOperators
+  >>> import Prelude
+  >>> import Data.KVList (empty, KVList, (:=)((:=)), (&.), (&=))
+  >>> let sampleList = empty &= #foo := "str" &= #bar := 34
+  >>> type SampleList = KVList '[ "foo" := String, "bar" := Int ]
+-}
+
+{-| A value with type level key.
+-}
+data KVList (kvs :: [Type]) where
+  KVNil :: KVList '[]
+  KVCons :: (KnownSymbol key) => key := v -> KVList xs -> KVList ((key := v) ': xs)
+
+{-| -}
+empty :: KVList '[]
+empty = KVNil
+
+(&=) :: (KnownSymbol k, Appended kvs '[k := v] ~ appended) => KVList kvs -> (k := v) -> KVList appended
+(&=) kvs kv = append kvs (singleton kv)
+{-# INLINE (&=) #-}
+
+infixl 1 &=
+
+{-| -}
+kvcons :: (KnownSymbol k) => (k := v) -> KVList kvs -> KVList ((k := v) ': kvs)
+kvcons = KVCons
+
+{-| -}
+data (key :: Symbol) := (value :: Type) where
+  (:=) :: ListKey a -> b -> a := b
+infix 2 :=
+
+deriving instance (Show value) => Show (key := value)
+
+{-| -}
+type HasKey (key :: Symbol) (kvs :: [Type]) (v :: Type) = HasKey_ key kvs kvs v
+
+type family HasKey_ (key :: Symbol) (kvs :: [Type]) (orig :: [Type]) (v :: Type) :: Constraint where
+  HasKey_ key '[] '[] v = TypeError ('Text "The KVList is empty.")
+  HasKey_ key '[] orig v = TypeError ('Text "The Key is not in the KVList.")
+  HasKey_ key ((key := val) ': _) _ v = (val ~ v)
+  HasKey_ key (_ ': kvs) orig v = HasKey_ key kvs orig v
+
+{-| -}
+type family Appended kvs1 kv2 :: [Type] where
+  Appended '[] kv2 = kv2
+  Appended (kv ': kvs) kv2 =
+    kv ': Appended kvs kv2
+
+{-| -}
+append :: (Appended kvs1 kvs2 ~ appended) => KVList kvs1 -> KVList kvs2 -> KVList appended
+append KVNil kvs2 = kvs2
+append (KVCons kv kvs) kvs2 = KVCons kv (append kvs kvs2)
+
+
+{-| -}
+singleton :: (KnownSymbol k) => (k := v) -> KVList '[ k := v ]
+singleton kv = KVCons kv KVNil
+
+
+{-| -}
+get :: (KnownSymbol key, HasKey key kvs v) => ListKey key -> KVList kvs -> v
+get p kvs = get_ p kvs kvs
+
+get_ :: (KnownSymbol key, HasKey key orig v) => ListKey key -> KVList kvs -> KVList orig -> v
+get_ _ KVNil KVNil = error "Unreachable: The KVList is empty."
+get_ _ KVNil _ = error "Unreachable: The Key is not in the KVList."
+get_ p (KVCons (k := v) kvs) orig =
+  if typeOf p == typeOf k then
+    unsafeCoerce v
+  else
+    get_ p kvs orig
+
+
+{-| -}
+(&.) :: (KnownSymbol key, HasKey key kvs v) => KVList kvs -> ListKey key -> v
+(&.) kvs k = get k kvs
+infixl 9 &.
+
+{-| 'ListKey' is just a proxy, but needed to implement a non-orphan 'IsLabel' instance.
+In most cases, you only need to create a `ListKey` instance with @OverloadedLabels@, such as `#foo`.
+-}
+data ListKey (t :: Symbol)
+    = ListKey
+    deriving (Show, Eq, Typeable)
+
+instance l ~ l' => IsLabel (l :: Symbol) (ListKey l') where
+#if MIN_VERSION_base(4, 10, 0)
+    fromLabel = ListKey
+#else
+    fromLabel _ = ListKey
+#endif
diff --git a/test/DocTest.hs b/test/DocTest.hs
new file mode 100644
--- /dev/null
+++ b/test/DocTest.hs
@@ -0,0 +1,57 @@
+module Main (main) where
+
+import Prelude
+
+import System.FilePath.Glob (glob)
+import Test.DocTest (doctest)
+
+main :: IO ()
+main = glob "src/**/*.hs" >>= doDocTest
+
+doDocTest :: [String] -> IO ()
+doDocTest options =
+  doctest $
+    options <>
+    ghcExtensions
+
+ghcExtensions :: [String]
+ghcExtensions =
+    [ "-XBangPatterns"
+    , "-XBinaryLiterals"
+    , "-XConstraintKinds"
+    , "-XDataKinds"
+    , "-XDefaultSignatures"
+    , "-XDeriveDataTypeable"
+    , "-XDeriveFoldable"
+    , "-XDeriveFunctor"
+    , "-XDeriveGeneric"
+    , "-XDeriveTraversable"
+    , "-XDoAndIfThenElse"
+    , "-XDuplicateRecordFields"
+    , "-XEmptyDataDecls"
+    , "-XExistentialQuantification"
+    , "-XFlexibleContexts"
+    , "-XFlexibleInstances"
+    , "-XFunctionalDependencies"
+    , "-XGADTs"
+    , "-XGeneralizedNewtypeDeriving"
+    , "-XInstanceSigs"
+    , "-XKindSignatures"
+    , "-XLambdaCase"
+    , "-XMultiParamTypeClasses"
+    , "-XMultiWayIf"
+    , "-XNamedFieldPuns"
+    , "-XNoImplicitPrelude"
+    , "-XOverloadedStrings"
+    , "-XPartialTypeSignatures"
+    , "-XPatternGuards"
+    , "-XPolyKinds"
+    , "-XRankNTypes"
+    , "-XRecordWildCards"
+    , "-XScopedTypeVariables"
+    , "-XStandaloneDeriving"
+    , "-XTupleSections"
+    , "-XTypeFamilies"
+    , "-XTypeSynonymInstances"
+    , "-XViewPatterns"
+    ]
diff --git a/type-level-kv-list.cabal b/type-level-kv-list.cabal
new file mode 100644
--- /dev/null
+++ b/type-level-kv-list.cabal
@@ -0,0 +1,130 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+
+name:           type-level-kv-list
+version:        0.2.0.0
+synopsis:       Type level Key-Value list.
+description:    This library provides a brief implementation for extensible records.
+category:       Data
+homepage:       https://github.com/arowM/type-level-kv-list#readme
+bug-reports:    https://github.com/arowM/type-level-kv-list/issues
+author:         Sakura-chan the Goat
+maintainer:     arow.okamoto+github@gmail.com
+copyright:      2016 Sakura-chan the Goat
+license:        MIT
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+
+source-repository head
+  type: git
+  location: https://github.com/arowM/type-level-kv-list
+
+library
+  exposed-modules:
+      Data.KVList
+  other-modules:
+      Paths_type_level_kv_list
+  hs-source-dirs:
+      src
+  default-extensions:
+      BangPatterns
+      BinaryLiterals
+      ConstraintKinds
+      DataKinds
+      DefaultSignatures
+      DeriveDataTypeable
+      DeriveFoldable
+      DeriveFunctor
+      DeriveGeneric
+      DeriveTraversable
+      DoAndIfThenElse
+      DuplicateRecordFields
+      EmptyDataDecls
+      ExistentialQuantification
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      InstanceSigs
+      KindSignatures
+      LambdaCase
+      MultiParamTypeClasses
+      MultiWayIf
+      NamedFieldPuns
+      OverloadedStrings
+      PartialTypeSignatures
+      PatternGuards
+      PolyKinds
+      RankNTypes
+      RecordWildCards
+      ScopedTypeVariables
+      StandaloneDeriving
+      Strict
+      StrictData
+      TupleSections
+      TypeFamilies
+      TypeSynonymInstances
+      ViewPatterns
+  ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints
+  build-depends:
+      base >=4.7 && <5
+  default-language: Haskell2010
+
+test-suite doctest
+  type: exitcode-stdio-1.0
+  main-is: DocTest.hs
+  hs-source-dirs:
+      test
+  default-extensions:
+      BangPatterns
+      BinaryLiterals
+      ConstraintKinds
+      DataKinds
+      DefaultSignatures
+      DeriveDataTypeable
+      DeriveFoldable
+      DeriveFunctor
+      DeriveGeneric
+      DeriveTraversable
+      DoAndIfThenElse
+      DuplicateRecordFields
+      EmptyDataDecls
+      ExistentialQuantification
+      FlexibleContexts
+      FlexibleInstances
+      FunctionalDependencies
+      GADTs
+      GeneralizedNewtypeDeriving
+      InstanceSigs
+      KindSignatures
+      LambdaCase
+      MultiParamTypeClasses
+      MultiWayIf
+      NamedFieldPuns
+      OverloadedStrings
+      PartialTypeSignatures
+      PatternGuards
+      PolyKinds
+      RankNTypes
+      RecordWildCards
+      ScopedTypeVariables
+      StandaloneDeriving
+      Strict
+      StrictData
+      TupleSections
+      TypeFamilies
+      TypeSynonymInstances
+      ViewPatterns
+  ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints
+  build-depends:
+      Glob
+    , base >=4.7 && <5
+    , doctest
+    , type-level-kv-list
+  default-language: Haskell2010