diff --git a/src/Language/Json/Type.hs b/src/Language/Json/Type.hs
index 8205b6c..5489898 100644
--- a/src/Language/Json/Type.hs
+++ b/src/Language/Json/Type.hs
@@ -31,6 +31,8 @@ import qualified Data.Traversable as Traversable
 import qualified Test.QuickCheck.Gen as Gen
 import qualified Data.Map as Map
 
+-- | Types a 'Json.Value' can have.
+
 data Type
   = Null
   | All -- the inverse of any, supertype of all types
@@ -112,14 +114,18 @@ infer = \case
   Value.Object fields -> Object $ infer <$> fields
 
 
+-- | Documents the differences found when checking conformity.
+
 data Mismatch = Mismatch
-  { expected :: Type
-  , inferred :: Type
-  , value    :: Value
-  , path     :: [Path]
+  { expected :: Type -- ^ type expected in the layout
+  , inferred :: Type -- ^ type inferred from the input
+  , value    :: Value -- ^ value present in the input
+  , path     :: [Path] -- ^ path to get to the value
   }
   deriving stock (Show, Eq, Ord)
 
+-- | Virtual Field alias
+
 instance HasField "actual" Mismatch Type where
   getField :: Mismatch -> Type
   getField = (.inferred)
@@ -130,6 +136,8 @@ conforms :: Type -> Json.Value -> [Mismatch]
 conforms = conforms' []
 
 
+-- | Annotate found nonconformities with the value path.
+
 conforms' :: [Path] -> Type -> Value -> [Mismatch]
 conforms' path layout value = case (value, layout) of
   (_, All) -> mempty -- matches all the types