diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.0.0.1] - 2026-02-11
+
+* Made the Spec return type more general: TestDef outers ()
+
 ## [1.0.0.0] - 2021-11-20
 
 * Compatibility with `genvalidity >= 1.0.0.0`
diff --git a/genvalidity-sydtest-aeson.cabal b/genvalidity-sydtest-aeson.cabal
--- a/genvalidity-sydtest-aeson.cabal
+++ b/genvalidity-sydtest-aeson.cabal
@@ -1,11 +1,11 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.34.4.
+-- This file has been generated from package.yaml by hpack version 0.38.3.
 --
 -- see: https://github.com/sol/hpack
 
 name:           genvalidity-sydtest-aeson
-version:        1.0.0.0
+version:        1.0.0.1
 synopsis:       Standard spec's for aeson-related instances in sydtest
 category:       Testing
 homepage:       http://cs-syd.eu
@@ -36,7 +36,6 @@
       QuickCheck
     , aeson
     , base >=4.9 && <=5
-    , bytestring
     , deepseq
     , genvalidity >=1.0
     , genvalidity-sydtest
@@ -55,15 +54,12 @@
   build-tool-depends:
       sydtest-discover:sydtest-discover
   build-depends:
-      QuickCheck
-    , aeson
+      aeson
     , base >=4.9 && <=5
     , genvalidity
     , genvalidity-aeson
-    , genvalidity-sydtest
     , genvalidity-sydtest-aeson
     , genvalidity-text
     , sydtest
     , text
-    , validity >=0.9
   default-language: Haskell2010
diff --git a/src/Test/Syd/Validity/Aeson.hs b/src/Test/Syd/Validity/Aeson.hs
--- a/src/Test/Syd/Validity/Aeson.hs
+++ b/src/Test/Syd/Validity/Aeson.hs
@@ -30,9 +30,9 @@
 --
 -- > jsonSpec @Int
 jsonSpec ::
-  forall a.
+  forall a outers.
   (Show a, Eq a, Typeable a, GenValid a, FromJSON a, ToJSON a) =>
-  Spec
+  TestDef outers ()
 jsonSpec = jsonSpecOnGen (genValid @a) "valid" shrinkValid
 
 -- | Standard test spec for properties of JSON-related functions for arbitrary values
@@ -41,9 +41,9 @@
 --
 -- > jsonSpecOnArbitrary @Int
 jsonSpecOnArbitrary ::
-  forall a.
+  forall a outers.
   (Show a, Eq a, Typeable a, Arbitrary a, FromJSON a, ToJSON a) =>
-  Spec
+  TestDef outers ()
 jsonSpecOnArbitrary = jsonSpecOnGen (arbitrary @a) "arbitrary" shrink
 
 -- | Standard test spec for properties of JSON-related functions for a given generator (and a name for that generator).
@@ -52,12 +52,12 @@
 --
 -- > jsonSpecOnGen (genListOf $ pure 'a') "sequence of 'a's"
 jsonSpecOnGen ::
-  forall a.
+  forall a outers.
   (Show a, Eq a, Typeable a, FromJSON a, ToJSON a) =>
   Gen a ->
   String ->
   (a -> [a]) ->
-  Spec
+  TestDef outers ()
 jsonSpecOnGen gen genname s =
   parallel $ do
     let name = nameOf @a
@@ -71,7 +71,7 @@
                 name ++ "\""
               ]
           )
-          $ neverFailsToEncodeOnGen gen s
+        $ neverFailsToEncodeOnGen gen s
       describe
         ( "decode :: Data.ByteString.Lazy.ByteString -> Either String "
             ++ name
@@ -83,7 +83,7 @@
                 name ++ "\"" ++ "'s"
               ]
           )
-          $ encodeAndDecodeAreInversesOnGen gen s
+        $ encodeAndDecodeAreInversesOnGen gen s
 
 -- |
 --