diff --git a/examples/hackage.hs b/examples/hackage.hs
index c605f6a..9204621 100644
--- a/examples/hackage.hs
+++ b/examples/hackage.hs
@@ -27,7 +27,7 @@ instance ToSchema UserSummary where
     usernameSchema <- declareSchemaRef (Proxy :: Proxy Username)
     useridSchema   <- declareSchemaRef (Proxy :: Proxy Int)
     return $ NamedSchema (Just "UserSummary") $ mempty
-      & type_ .~ SwaggerObject
+      & type_ ?~ SwaggerObject
       & properties .~
           [ ("summaryUsername", usernameSchema )
           , ("summaryUserid"  , useridSchema   )
diff --git a/src/Data/Swagger/Internal.hs b/src/Data/Swagger/Internal.hs
index cd1b553..5589833 100644
--- a/src/Data/Swagger/Internal.hs
+++ b/src/Data/Swagger/Internal.hs
@@ -610,7 +610,7 @@ data ParamSchema (t :: SwaggerKind *) = ParamSchema
   , _paramSchemaMultipleOf :: Maybe Scientific
   } deriving (Eq, Show, Generic, Typeable)
 
-deriving instance (Typeable k, Data (SwaggerType k), Data (SwaggerItems k)) => Data (ParamSchema k)
+deriving instance (Typeable k, Data (Maybe (SwaggerType k)), Data (SwaggerItems k)) => Data (ParamSchema k)
 
 data Xml = Xml
   { -- | Replaces the name of the element/attribute used for the described schema property.
diff --git a/src/Data/Swagger/Internal/Schema.hs b/src/Data/Swagger/Internal/Schema.hs
index f127604..74a4060 100644
--- a/src/Data/Swagger/Internal/Schema.hs
+++ b/src/Data/Swagger/Internal/Schema.hs
@@ -335,7 +335,7 @@ sketchSchema = sketch . toJSON
 
     go Null       = mempty & type_ ?~ SwaggerNull
     go (Bool _)   = mempty & type_ ?~ SwaggerBoolean
-    go (String _) = mempty & type_   ?~ SwaggerString
+    go (String _) = mempty & type_ ?~ SwaggerString
     go (Number _) = mempty & type_ ?~ SwaggerNumber
     go (Array xs) = mempty
       & type_   ?~ SwaggerArray
diff --git a/src/Data/Swagger/Internal/Schema/Validation.hs b/src/Data/Swagger/Internal/Schema/Validation.hs
index e8986fd..7b0f3ed 100644
--- a/src/Data/Swagger/Internal/Schema/Validation.hs
+++ b/src/Data/Swagger/Internal/Schema/Validation.hs
@@ -382,45 +382,44 @@ inferParamSchemaTypes sch = concat
 
 validateSchemaType :: Value -> Validation Schema ()
 validateSchemaType value = withSchema $ \sch ->
-  case sch ^. type_ of
-    Just explicitType -> validateSchemaTypeAs explicitType value
-    Nothing ->
-      case inferSchemaTypes sch of
-        [t] -> validateSchemaTypeAs t value
-        []  -> invalid $ "unable to infer type for schema, please provide type explicitly"
-        ts  -> invalid $ "unable to infer type for schema, possible candidates: " ++ intercalate ", " (map show ts)
-
-validateSchemaTypeAs
-  :: SwaggerType 'SwaggerKindSchema -> Value -> Validation Schema ()
-validateSchemaTypeAs t value =
-  case (t, value) of
-    (SwaggerNull,    Null)       -> valid
-    (SwaggerBoolean, Bool _)     -> valid
-    (SwaggerInteger, Number n)   -> sub_ paramSchema (validateInteger n)
-    (SwaggerNumber,  Number n)   -> sub_ paramSchema (validateNumber n)
-    (SwaggerString,  String s)   -> sub_ paramSchema (validateString s)
-    (SwaggerArray,   Array xs)   -> sub_ paramSchema (validateArray xs)
-    (SwaggerObject,  Object o)   -> validateObject o
-    _ -> invalid $ "expected JSON value of type " ++ show t
+  case (sch ^. type_, value) of
+    (Just SwaggerNull,    Null)       -> valid
+    (Just SwaggerBoolean, Bool _)     -> valid
+    (Just SwaggerInteger, Number n)   -> sub_ paramSchema (validateInteger n)
+    (Just SwaggerNumber,  Number n)   -> sub_ paramSchema (validateNumber n)
+    (Just SwaggerString,  String s)   -> sub_ paramSchema (validateString s)
+    (Just SwaggerArray,   Array xs)   -> sub_ paramSchema (validateArray xs)
+    (Just SwaggerObject,  Object o)   -> validateObject o
+    (Nothing, Null)                   -> valid
+    (Nothing, Bool _)                 -> valid
+    -- Number by default
+    (Nothing, Number n)               -> sub_ paramSchema (validateNumber n)
+    (Nothing, String s)               -> sub_ paramSchema (validateString s)
+    (Nothing, Array xs)               -> sub_ paramSchema (validateArray xs)
+    (Nothing, Object o)               -> validateObject o
+    param@(t, _) -> invalid $ "expected JSON value of type " ++ showType param
 
 validateParamSchemaType :: Value -> Validation (ParamSchema t) ()
 validateParamSchemaType value = withSchema $ \sch ->
-  case sch ^. type_ of
-    Just explicitType -> validateParamSchemaTypeAs explicitType value
-    Nothing ->
-      case inferParamSchemaTypes sch of
-        [t] -> validateParamSchemaTypeAs t value
-        []  -> invalid $ "unable to infer type for schema, please provide type explicitly"
-        ts  -> invalid $ "unable to infer type for schema, possible candidates: " ++ intercalate ", " (map show ts)
-
-validateParamSchemaTypeAs
-  :: SwaggerType t -> Value -> Validation (ParamSchema t) ()
-validateParamSchemaTypeAs t value =
-  case (t, value) of
-    (SwaggerBoolean, Bool _)     -> valid
-    (SwaggerInteger, Number n)   -> validateInteger n
-    (SwaggerNumber,  Number n)   -> validateNumber n
-    (SwaggerString,  String s)   -> validateString s
-    (SwaggerArray,   Array xs)   -> validateArray xs
-    _ -> invalid $ "expected JSON value of type " ++ show t
-
+  case (sch ^. type_, value) of
+    (Just SwaggerBoolean, Bool _)     -> valid
+    (Just SwaggerInteger, Number n)   -> validateInteger n
+    (Just SwaggerNumber,  Number n)   -> validateNumber n
+    (Just SwaggerString,  String s)   -> validateString s
+    (Just SwaggerArray,   Array xs)   -> validateArray xs
+    (Nothing, Bool _)                 -> valid
+    -- Number by default
+    (Nothing, Number n)               -> validateNumber n
+    (Nothing, String s)               -> validateString s
+    (Nothing, Array xs)               -> validateArray xs
+    (t, _) -> invalid $ "expected JSON value of type " ++ show t
+    param@(t, _) -> invalid $ "expected JSON value of type " ++ showType param
+
+showType :: (Maybe (SwaggerType t), Value) -> String
+showType (Just type_, _)     = show type_
+showType (Nothing, Null)     = "SwaggerNull"
+showType (Nothing, Bool _)   = "SwaggerBoolean"
+showType (Nothing, Number _) = "SwaggerNumber"
+showType (Nothing, String _) = "SwaggerString"
+showType (Nothing, Array _)  = "SwaggerArray"
+showType (Nothing, Object _) = "SwaggerObject"