diff --git a/Data/GraphQL/AST.hs b/Data/GraphQL/AST.hs
index 98bbe9f..58ae20d 100644
--- a/Data/GraphQL/AST.hs
+++ b/Data/GraphQL/AST.hs
@@ -17,7 +17,6 @@ newtype Document = Document [Definition] deriving (Eq,Show)
 
 data Definition = DefinitionOperation OperationDefinition
                 | DefinitionFragment  FragmentDefinition
-                | DefinitionType      TypeDefinition
                   deriving (Eq,Show)
 
 data OperationDefinition = Query    Node
@@ -127,48 +126,3 @@ newtype ListType = ListType Type deriving (Eq,Show)
 data NonNullType = NonNullTypeNamed NamedType
                  | NonNullTypeList  ListType
                    deriving (Eq,Show)
-
--- * Type definition
-
-data TypeDefinition = TypeDefinitionObject        ObjectTypeDefinition
-                    | TypeDefinitionInterface     InterfaceTypeDefinition
-                    | TypeDefinitionUnion         UnionTypeDefinition
-                    | TypeDefinitionScalar        ScalarTypeDefinition
-                    | TypeDefinitionEnum          EnumTypeDefinition
-                    | TypeDefinitionInputObject   InputObjectTypeDefinition
-                    | TypeDefinitionTypeExtension TypeExtensionDefinition
-                      deriving (Eq,Show)
-
-data ObjectTypeDefinition = ObjectTypeDefinition Name Interfaces [FieldDefinition]
-                            deriving (Eq,Show)
-
-type Interfaces = [NamedType]
-
-data FieldDefinition = FieldDefinition Name ArgumentsDefinition Type
-                       deriving (Eq,Show)
-
-type ArgumentsDefinition = [InputValueDefinition]
-
-data InputValueDefinition = InputValueDefinition Name Type (Maybe DefaultValue)
-                            deriving (Eq,Show)
-
-data InterfaceTypeDefinition = InterfaceTypeDefinition Name [FieldDefinition]
-                               deriving (Eq,Show)
-
-data UnionTypeDefinition = UnionTypeDefinition Name [NamedType]
-                           deriving (Eq,Show)
-
-newtype ScalarTypeDefinition = ScalarTypeDefinition Name
-                            deriving (Eq,Show)
-
-data EnumTypeDefinition = EnumTypeDefinition Name [EnumValueDefinition]
-                          deriving (Eq,Show)
-
-newtype EnumValueDefinition = EnumValueDefinition Name
-                              deriving (Eq,Show)
-
-data InputObjectTypeDefinition = InputObjectTypeDefinition Name [InputValueDefinition]
-                                 deriving (Eq,Show)
-
-newtype TypeExtensionDefinition = TypeExtensionDefinition ObjectTypeDefinition
-                                  deriving (Eq,Show)
diff --git a/Data/GraphQL/Encoder.hs b/Data/GraphQL/Encoder.hs
index a418893..0cf878e 100644
--- a/Data/GraphQL/Encoder.hs
+++ b/Data/GraphQL/Encoder.hs
@@ -17,7 +17,6 @@ document (Document defs) = (`snoc` '\n') . mconcat $ definition <$> defs
 definition :: Definition -> Text
 definition (DefinitionOperation x) = operationDefinition x
 definition (DefinitionFragment  x) = fragmentDefinition x
-definition (DefinitionType      x) = typeDefinition x
 
 operationDefinition :: OperationDefinition -> Text
 operationDefinition (Query    n) = "query "    <> node n
@@ -139,73 +138,6 @@ nonNullType :: NonNullType -> Text
 nonNullType (NonNullTypeNamed (NamedType x)) = x <> "!"
 nonNullType (NonNullTypeList  x) = listType x <> "!"
 
-typeDefinition :: TypeDefinition -> Text
-typeDefinition (TypeDefinitionObject        x) = objectTypeDefinition x
-typeDefinition (TypeDefinitionInterface     x) = interfaceTypeDefinition x
-typeDefinition (TypeDefinitionUnion         x) = unionTypeDefinition x
-typeDefinition (TypeDefinitionScalar        x) = scalarTypeDefinition x
-typeDefinition (TypeDefinitionEnum          x) = enumTypeDefinition x
-typeDefinition (TypeDefinitionInputObject   x) = inputObjectTypeDefinition x
-typeDefinition (TypeDefinitionTypeExtension x) = typeExtensionDefinition x
-
-objectTypeDefinition :: ObjectTypeDefinition -> Text
-objectTypeDefinition (ObjectTypeDefinition name ifaces fds) =
-    "type " <> name
-            <> optempty (spaced . interfaces) ifaces
-            <> optempty fieldDefinitions fds
-
-interfaces :: Interfaces -> Text
-interfaces = ("implements " <>) . spaces namedType
-
-fieldDefinitions :: [FieldDefinition] -> Text
-fieldDefinitions = bracesCommas fieldDefinition
-
-fieldDefinition :: FieldDefinition -> Text
-fieldDefinition (FieldDefinition name args ty) =
-    name <> optempty argumentsDefinition args
-         <> ":"
-         <> type_ ty
-
-argumentsDefinition :: ArgumentsDefinition -> Text
-argumentsDefinition = parensCommas inputValueDefinition
-
-interfaceTypeDefinition :: InterfaceTypeDefinition -> Text
-interfaceTypeDefinition (InterfaceTypeDefinition name fds) =
-    "interface " <> name <> fieldDefinitions fds
-
-unionTypeDefinition :: UnionTypeDefinition -> Text
-unionTypeDefinition (UnionTypeDefinition name ums) =
-    "union " <> name <> "=" <> unionMembers ums
-
-unionMembers :: [NamedType] -> Text
-unionMembers = intercalate "|" . fmap namedType
-
-scalarTypeDefinition :: ScalarTypeDefinition -> Text
-scalarTypeDefinition (ScalarTypeDefinition name) = "scalar " <> name
-
-enumTypeDefinition :: EnumTypeDefinition -> Text
-enumTypeDefinition (EnumTypeDefinition name evds) =
-    "enum " <> name
-            <> bracesCommas enumValueDefinition evds
-
-enumValueDefinition :: EnumValueDefinition -> Text
-enumValueDefinition (EnumValueDefinition name) = name
-
-inputObjectTypeDefinition :: InputObjectTypeDefinition -> Text
-inputObjectTypeDefinition (InputObjectTypeDefinition name ivds) =
-    "input " <> name <> inputValueDefinitions ivds
-
-inputValueDefinitions :: [InputValueDefinition] -> Text
-inputValueDefinitions = bracesCommas inputValueDefinition
-
-inputValueDefinition :: InputValueDefinition -> Text
-inputValueDefinition (InputValueDefinition name ty dv) =
-    name <> ":" <> type_ ty <> maybe mempty defaultValue dv
-
-typeExtensionDefinition :: TypeExtensionDefinition -> Text
-typeExtensionDefinition (TypeExtensionDefinition otd) =
-    "extend " <> objectTypeDefinition otd
-
 -- * Internal
 
 spaced :: Text -> Text
diff --git a/Data/GraphQL/Parser.hs b/Data/GraphQL/Parser.hs
index 160efad..2e72a3a 100644
--- a/Data/GraphQL/Parser.hs
+++ b/Data/GraphQL/Parser.hs
@@ -22,7 +22,6 @@ import Data.Attoparsec.Text
   , manyTill
   , option
   , peekChar
-  , sepBy1
   , takeWhile
   , takeWhile1
   )
@@ -54,7 +53,6 @@ document = whiteSpace
 definition :: Parser Definition
 definition = DefinitionOperation <$> operationDefinition
          <|> DefinitionFragment  <$> fragmentDefinition
-         <|> DefinitionType      <$> typeDefinition
          <?> "definition error!"
 
 operationDefinition :: Parser OperationDefinition
@@ -207,96 +205,6 @@ nonNullType = NonNullTypeNamed <$> namedType <* tok "!"
           <|> NonNullTypeList  <$> listType  <* tok "!"
           <?> "nonNullType error!"
 
--- * Type Definition
-
-typeDefinition :: Parser TypeDefinition
-typeDefinition =
-        TypeDefinitionObject        <$> objectTypeDefinition
-    <|> TypeDefinitionInterface     <$> interfaceTypeDefinition
-    <|> TypeDefinitionUnion         <$> unionTypeDefinition
-    <|> TypeDefinitionScalar        <$> scalarTypeDefinition
-    <|> TypeDefinitionEnum          <$> enumTypeDefinition
-    <|> TypeDefinitionInputObject   <$> inputObjectTypeDefinition
-    <|> TypeDefinitionTypeExtension <$> typeExtensionDefinition
-    <?> "typeDefinition error!"
-
-objectTypeDefinition :: Parser ObjectTypeDefinition
-objectTypeDefinition = ObjectTypeDefinition
-    <$  tok "type"
-    <*> name
-    <*> optempty interfaces
-    <*> fieldDefinitions
-
-interfaces :: Parser Interfaces
-interfaces = tok "implements" *> many1 namedType
-
-fieldDefinitions :: Parser [FieldDefinition]
-fieldDefinitions = braces $ many1 fieldDefinition
-
-fieldDefinition :: Parser FieldDefinition
-fieldDefinition = FieldDefinition
-    <$> name
-    <*> optempty argumentsDefinition
-    <*  tok ":"
-    <*> type_
-
-argumentsDefinition :: Parser ArgumentsDefinition
-argumentsDefinition = parens $ many1 inputValueDefinition
-
-interfaceTypeDefinition :: Parser InterfaceTypeDefinition
-interfaceTypeDefinition = InterfaceTypeDefinition
-    <$  tok "interface"
-    <*> name
-    <*> fieldDefinitions
-
-unionTypeDefinition :: Parser UnionTypeDefinition
-unionTypeDefinition = UnionTypeDefinition
-    <$  tok "union"
-    <*> name
-    <*  tok "="
-    <*> unionMembers
-
-unionMembers :: Parser [NamedType]
-unionMembers = namedType `sepBy1` tok "|"
-
-scalarTypeDefinition :: Parser ScalarTypeDefinition
-scalarTypeDefinition = ScalarTypeDefinition
-    <$  tok "scalar"
-    <*> name
-
-enumTypeDefinition :: Parser EnumTypeDefinition
-enumTypeDefinition = EnumTypeDefinition
-    <$  tok "enum"
-    <*> name
-    <*> enumValueDefinitions
-
-enumValueDefinitions :: Parser [EnumValueDefinition]
-enumValueDefinitions = braces $ many1 enumValueDefinition
-
-enumValueDefinition :: Parser EnumValueDefinition
-enumValueDefinition = EnumValueDefinition <$> name
-
-inputObjectTypeDefinition :: Parser InputObjectTypeDefinition
-inputObjectTypeDefinition = InputObjectTypeDefinition
-    <$  tok "input"
-    <*> name
-    <*> inputValueDefinitions
-
-inputValueDefinitions :: Parser [InputValueDefinition]
-inputValueDefinitions = braces $ many1 inputValueDefinition
-
-inputValueDefinition :: Parser InputValueDefinition
-inputValueDefinition = InputValueDefinition
-    <$> name
-    <*  tok ":"
-    <*> type_
-    <*> optional defaultValue
-
-typeExtensionDefinition :: Parser TypeExtensionDefinition
-typeExtensionDefinition = TypeExtensionDefinition
-    <$  tok "extend"
-    <*> objectTypeDefinition
-
 -- * Internal
 
 tok :: Parser a -> Parser a