diff --git a/ChangeLog.md b/ChangeLog.md
new file mode 100644
--- /dev/null
+++ b/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for hexomorph
+
+## Unreleased changes
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
+Corresponding Source for the Combined Work, excluding any source code
+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
+  The "Corresponding Application Code" for a Combined Work means the
+object code and/or source code for the Application, including any data
+and utility programs needed for reproducing the Combined Work from the
+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
+without being bound by section 3 of the GNU GPL.
+
+  2. Conveying Modified Versions.
+
+  If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
+that uses the facility (other than as an argument passed when the
+facility is invoked), then you may convey a copy of the modified
+version:
+
+   a) under this License, provided that you make a good faith effort to
+   ensure that, in the event an Application does not supply the
+   function or data, the facility still operates, and performs
+   whatever part of its purpose remains meaningful, or
+
+   b) under the GNU GPL, with none of the additional permissions of
+   this License applicable to that copy.
+
+  3. Object Code Incorporating Material from Library Header Files.
+
+  The object code form of an Application may incorporate material from
+a header file that is part of the Library.  You may convey such object
+code under terms of your choice, provided that, if the incorporated
+material is not limited to numerical parameters, data structure
+layouts and accessors, or small macros, inline functions and templates
+(ten or fewer lines in length), you do both of the following:
+
+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the object code with a copy of the GNU GPL and this license
+   document.
+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
+taken together, effectively do not restrict modification of the
+portions of the Library contained in the Combined Work and reverse
+engineering for debugging such modifications, if you also do each of
+the following:
+
+   a) Give prominent notice with each copy of the Combined Work that
+   the Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the Combined Work with a copy of the GNU GPL and this license
+   document.
+
+   c) For a Combined Work that displays copyright notices during
+   execution, include the copyright notice for the Library among
+   these notices, as well as a reference directing the user to the
+   copies of the GNU GPL and this license document.
+
+   d) Do one of the following:
+
+       0) Convey the Minimal Corresponding Source under the terms of this
+       License, and the Corresponding Application Code in a form
+       suitable for, and under terms that permit, the user to
+       recombine or relink the Application with a modified version of
+       the Linked Version to produce a modified Combined Work, in the
+       manner specified by section 6 of the GNU GPL for conveying
+       Corresponding Source.
+
+       1) Use a suitable shared library mechanism for linking with the
+       Library.  A suitable mechanism is one that (a) uses at run time
+       a copy of the Library already present on the user's computer
+       system, and (b) will operate properly with a modified version
+       of the Library that is interface-compatible with the Linked
+       Version.
+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
+   GNU GPL, and only to the extent that such information is
+   necessary to install and execute a modified version of the
+   Combined Work produced by recombining or relinking the
+   Application with a modified version of the Linked Version. (If
+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
+   Code. If you use option 4d1, you must provide the Installation
+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
+   conveyed under the terms of this License.
+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,4 @@
+# Haskell Schema Core
+
+This is the core module of the the Haskell Schema set of libraries and provides with the basic elements needed to define your own schemas.
+To be able to use this library you will need to combine it with one or more of the additional companion packages.
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/hschema.cabal b/hschema.cabal
new file mode 100644
--- /dev/null
+++ b/hschema.cabal
@@ -0,0 +1,53 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.31.0.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: 61456a052d486027e62bffc9af3700c01118a4cf0b5aa48e39ff96e59fb889d5
+
+name:           hschema
+version:        0.0.1.0
+synopsis:       Describe schemas for your Haskell data types.
+description:    Please see the README on GitHub at <https://github.com/alonsodomin/haskell-schema#readme>
+category:       Data,Schema
+homepage:       https://github.com/alonsodomin/haskell-schema#readme
+bug-reports:    https://github.com/alonsodomin/haskell-schema/issues
+author:         Antonio Alonso Dominguez
+maintainer:     alonso.domin@gmail.com
+copyright:      2018 Antonio Alonso Dominguez
+license:        LGPL-3
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+    ChangeLog.md
+
+source-repository head
+  type: git
+  location: https://github.com/alonsodomin/haskell-schema
+
+library
+  exposed-modules:
+      Control.Functor.HigherOrder
+      Data.Schema
+      Data.Schema.Internal.Types
+  other-modules:
+      Paths_hschema
+  hs-source-dirs:
+      src
+  build-depends:
+      base >=4.7 && <5
+    , comonad >=5.0 && <5.1
+    , contravariant
+    , free
+    , hashable
+    , invariant
+    , lens
+    , mtl
+    , natural-transformation
+    , profunctors
+    , text
+    , unordered-containers
+    , vector
+  default-language: Haskell2010
diff --git a/src/Control/Functor/HigherOrder.hs b/src/Control/Functor/HigherOrder.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Functor/HigherOrder.hs
@@ -0,0 +1,69 @@
+{-# LANGUAGE FlexibleContexts     #-}
+{-# LANGUAGE FlexibleInstances    #-}
+{-# LANGUAGE KindSignatures       #-}
+{-# LANGUAGE Rank2Types           #-}
+{-# LANGUAGE TypeOperators        #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+
+module Control.Functor.HigherOrder where
+
+import           Control.Natural
+
+type HAlgebra   f g = f g :~> g
+type HCoalgebra f g = g :~> f g
+
+class HFunctor (f :: ((* -> *) -> * -> *)) where
+  hfmap :: (m ~> n) -> f m ~> f n
+
+class HFunctor f => HPointed f where
+  hreturn :: Functor g => g a -> f g a
+
+class HFunctor f => HCopointed f where
+  hextract :: Functor g => f g a -> g a
+
+newtype HFix f a = HFix { unfix :: f (HFix f) a }
+
+data HEnvT
+  (f :: ((* -> *) -> * -> *))
+  (e :: *)
+  (g :: (* -> *))
+  (i :: *) = HEnvT { hask :: !e, hlocal :: f g i }
+
+newtype HMutu
+  (f :: ((* -> *) -> * -> *))
+  (g :: ((* -> *) -> * -> *))
+  (a :: *) = HMutu { unmutu :: f (g (HMutu f g)) a }
+
+instance HFunctor f => HFunctor (HEnvT f a) where
+  hfmap nt = \fa -> HEnvT (hask fa) ((hfmap nt) (hlocal fa))
+
+instance Functor (f g) => Functor (HEnvT f e g) where
+  fmap f env = HEnvT (hask env) (fmap f (hlocal env))
+
+type HCofree
+  (f :: ((* -> *) -> * -> *))
+  (a :: *) = HFix (HEnvT f a)
+
+hcofree :: a -> f (HCofree f a) b -> HCofree f a b
+hcofree a fhc = HFix (HEnvT a fhc)
+
+cataNT :: HFunctor f => HAlgebra f g -> HFix f ~> g
+cataNT alg = (unwrapNT alg) . nt
+  where nt hf = (hfmap (cataNT alg)) (unfix hf)
+
+anaNT :: HFunctor f => HCoalgebra f g -> g ~> HFix f
+anaNT coalg g = HFix $ (hfmap (anaNT coalg)) $ (unwrapNT coalg) g
+
+--hyloNT :: HFunctor f => HAlgebra f g -> HCoalgebra g f -> HFix f ~> HFix g
+
+hforgetAlg :: HAlgebra (HEnvT f a) (HFix f)
+hforgetAlg = wrapNT $ \env -> HFix $ hlocal env
+
+hforget :: HFunctor f => HCofree f a ~> HFix f
+hforget = cataNT hforgetAlg
+
+htagCoalg :: HFunctor f => a -> HCoalgebra (HEnvT f a) (HFix f)
+htagCoalg tag = wrapNT $ \hfix -> HEnvT tag (unfix hfix)
+
+htag :: HFunctor f => a -> HFix f ~> HCofree f a
+htag tag = anaNT (htagCoalg tag)
diff --git a/src/Data/Schema.hs b/src/Data/Schema.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Schema.hs
@@ -0,0 +1,61 @@
+{-# LANGUAGE RankNTypes #-}
+
+module Data.Schema
+     ( Field
+     , Fields
+     , field
+     , optional
+     , alt
+     , Schema
+     , HasSchema (..)
+     , prim
+     , const
+     , record
+     , asList
+     , toList
+     , oneOf
+     , alias
+     ) where
+
+import           Control.Functor.HigherOrder
+import           Control.Lens
+import           Data.Functor.Invariant
+import           Data.Hashable               (Hashable)
+import           Data.HashMap.Strict         (HashMap)
+import qualified Data.List.NonEmpty          as NEL
+import           Data.Schema.Internal.Types
+import           Data.Text                   (Text)
+import           Data.Vector                 (Vector)
+import qualified Data.Vector                 as Vector
+import           Prelude                     hiding (const, seq)
+
+-- | Define an alternative
+alt :: Text -> s b -> Prism' a b -> AltDef s a
+alt = AltDef
+
+-- | Define an annotated schema for primitives of type `p`
+prim :: p a -> Schema p a
+prim primAlg = Schema (HFix $ PrimitiveSchema primAlg)
+
+-- | Define a schema for a type that is always constant
+const :: a -> Schema p a
+const a = Schema (HFix (RecordSchema $ pure a))
+
+-- | Define the schema of record using the given fields
+record :: Fields (Schema p) a -> Schema p a
+record ps = Schema (HFix (RecordSchema $ hoistField unwrapSchema ps))
+
+-- | Define the schema of a list based on the element type
+asList :: Iso' (Vector a) [a]
+asList = iso Vector.toList Vector.fromList
+
+toList :: Schema p (Vector a) -> Schema p [a]
+toList = invmap Vector.toList Vector.fromList
+
+-- | Define the schema of an union (coproduct) type based on the given alternatives
+oneOf :: [AltDef (Schema p) a] -> Schema p a
+oneOf alts = Schema (HFix (UnionSchema $ fmap (hfmap unwrapSchema) $ NEL.fromList alts))
+
+-- | Define an schema alias that is isomorphic to another one using the given ISO transformation
+alias :: Iso' a b -> Schema p a -> Schema p b
+alias i base = invmap (view i) (view . from $ i) base
diff --git a/src/Data/Schema/Internal/Types.hs b/src/Data/Schema/Internal/Types.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Schema/Internal/Types.hs
@@ -0,0 +1,120 @@
+{-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE FlexibleContexts          #-}
+{-# LANGUAGE FlexibleInstances         #-}
+{-# LANGUAGE GADTs                     #-}
+{-# LANGUAGE LambdaCase                #-}
+{-# LANGUAGE MultiParamTypeClasses     #-}
+{-# LANGUAGE RankNTypes                #-}
+{-# LANGUAGE ScopedTypeVariables       #-}
+{-# LANGUAGE TypeFamilies              #-}
+{-# LANGUAGE TypeOperators             #-}
+{-# LANGUAGE TypeSynonymInstances      #-}
+
+module Data.Schema.Internal.Types where
+
+import           Control.Applicative.Free
+import           Control.Functor.HigherOrder
+import           Control.Lens                hiding (iso)
+import qualified Control.Lens                as Lens
+import           Control.Natural
+import           Data.Functor.Invariant
+import           Data.List.NonEmpty          (NonEmpty)
+import           Data.Profunctor
+import           Data.Text                   (Text)
+import qualified Data.Text                   as T
+import           Data.Vector                 (Vector)
+import           Prelude                     hiding (const, seq)
+
+-- | Metadata for a field of type `a`, belonging to the data type `o` and based on schema `s`
+data FieldDef o s a where
+  RequiredField :: Text -> s a -> Getter o a -> FieldDef o s a
+  OptionalField :: Text -> s a -> Getter o (Maybe a) -> FieldDef o s (Maybe a)
+
+fieldName :: FieldDef o s a -> Text
+fieldName (RequiredField name _ _) = name
+fieldName (OptionalField name _ _) = name
+
+instance HFunctor (FieldDef o) where
+  hfmap nt = \case
+    RequiredField name s acc -> RequiredField name (nt s) acc
+    OptionalField name s acc -> OptionalField name (nt s) acc
+
+-- | The type of a field of type `a`, belonging to the data type `o` and based on schema `s`
+newtype Field s o a = Field { unwrapField :: Ap (FieldDef o s) a }
+
+hoistField :: (m ~> n) -> Field m o a -> Field n o a
+hoistField nt (Field ap) = Field $ hoistAp (hfmap nt) ap
+
+-- | The set of fields for the data type `o` based on schema `s`
+type Fields s o = Field s o o
+
+instance Functor (Field s o) where
+  fmap f (Field x) = Field $ fmap f x
+
+instance Applicative (Field s o) where
+  pure x = Field $ Pure x
+  (Field x) <*> (Field y) = Field (x <*> y)
+
+instance Profunctor (Field s) where
+  lmap f (Field ap) = Field $ hoistAp (contraNT f) ap
+    where contraNT :: (n -> o) -> FieldDef o s ~> FieldDef n s
+          contraNT f = \case
+            RequiredField n s g -> RequiredField n s ((to f) . g)
+            OptionalField n s g -> OptionalField n s ((to f) . g)
+  rmap = fmap
+
+-- | Define a field
+field :: Text -> s a -> Getter o a -> Field s o a
+field name schema getter = Field $ liftAp (RequiredField name schema getter)
+
+optional :: Text -> s a -> Getter o (Maybe a) -> Field s o (Maybe a)
+optional name schema getter = Field $ liftAp (OptionalField name schema getter)
+
+-- | Metadata for an alternative of type `a` based on schema `s`
+data AltDef s a = forall b. AltDef
+  { altName   :: Text
+  , altSchema :: s b
+  , altPrism  :: Prism' a b
+  }
+
+instance HFunctor AltDef where
+  hfmap nt = \(AltDef name schema pr) -> AltDef name (nt schema) pr
+
+-- | Metadata for a schema `s` based on primitives `p` and representing type `a`
+data SchemaF p s a where
+  PrimitiveSchema :: p a -> SchemaF p s a
+  RecordSchema    :: Fields s a -> SchemaF p s a
+  UnionSchema     :: NonEmpty (AltDef s a) -> SchemaF p s a
+  AliasSchema     :: s a -> Iso' a b -> SchemaF p s b
+
+instance HFunctor (SchemaF p) where
+  hfmap nt = \case
+    PrimitiveSchema p         -> PrimitiveSchema p
+    RecordSchema (Field flds) -> RecordSchema . Field $ hoistAp (hfmap nt) flds
+    UnionSchema alts          -> UnionSchema $ fmap (hfmap nt) alts
+    AliasSchema base iso      -> AliasSchema (nt base) iso
+
+-- | The Schema type itself for a set of primitives `p`
+newtype Schema p a = Schema { unwrapSchema :: HFix (SchemaF p) a }
+
+instance Invariant (Schema p) where
+  invmap f g sch = case (unfix . unwrapSchema $ sch) of
+    AliasSchema base iso -> Schema . HFix $ AliasSchema base (iso . (Lens.iso f g))
+    otherwise            -> Schema . HFix $ AliasSchema (unwrapSchema sch) (Lens.iso f g)
+
+-- | An Schema has a HFunctor that performs a natural transformation of the primitive algebra of the Schema
+instance HFunctor Schema where
+  hfmap nt (Schema fsch) = Schema $ cataNT pfmapAlg fsch
+    where pfmapAlg = wrapNT $ \sch -> HFix $ pfmap nt sch
+
+          pfmap :: (p ~> q) -> SchemaF p s ~> SchemaF q s
+          pfmap nt = \case
+            PrimitiveSchema p    -> PrimitiveSchema (nt p)
+            RecordSchema fields  -> RecordSchema fields
+            UnionSchema alts     -> UnionSchema alts
+            AliasSchema base iso -> AliasSchema base iso
+
+class HasSchema a where
+  type PrimitivesOf a :: * -> *
+
+  getSchema :: Schema (PrimitivesOf a) a