diff --git a/src/Language/Json.hs b/src/Language/Json.hs
index d99ddcb..67de602 100644
--- a/src/Language/Json.hs
+++ b/src/Language/Json.hs
@@ -33,11 +33,11 @@ import Data.Array.Arbitrary (ArbitraryArray(getArbitraryArray))
 
 data Value
   = Null
-  | String Text
-  | Boolean Bool
-  | Number Rational
-  | Array (Array Natural Value)
-  | Object (Map Text Value)
+  | String  {-# UNPACK #-} !Text
+  | Boolean {-# UNPACK #-} !Bool
+  | Number  {-# UNPACK #-} !Rational
+  | Array   {-# UNPACK #-} !(Array Natural Value)
+  | Object  {-# UNPACK #-} !(Map Text Value)
   deriving (Show, Generic, Eq, Ord)
   deriving PrettySerialize via Generically Value