diff --git a/library/PostgreSQL/Binary/Encoding.hs b/library/PostgreSQL/Binary/Encoding.hs
--- a/library/PostgreSQL/Binary/Encoding.hs
+++ b/library/PostgreSQL/Binary/Encoding.hs
@@ -47,8 +47,10 @@
   interval_float,
   -- ** JSON
   json_bytes,
+  json_bytes_lazy,
   json_ast,
   jsonb_bytes,
+  jsonb_bytes_lazy,
   jsonb_ast,
 
   -- * Array
@@ -296,6 +298,11 @@
 json_bytes =
   B.json_bytes
 
+{-# INLINE json_bytes_lazy #-}
+json_bytes_lazy :: N.ByteString -> Encoding
+json_bytes_lazy =
+  B.json_bytes_lazy
+
 {-# INLINE json_ast #-}
 json_ast :: R.Value -> Encoding
 json_ast =
@@ -305,6 +312,11 @@
 jsonb_bytes :: ByteString -> Encoding
 jsonb_bytes =
   B.jsonb_bytes
+
+{-# INLINE jsonb_bytes_lazy #-}
+jsonb_bytes_lazy :: N.ByteString -> Encoding
+jsonb_bytes_lazy =
+  B.jsonb_bytes_lazy
 
 {-# INLINE jsonb_ast #-}
 jsonb_ast :: R.Value -> Encoding
diff --git a/library/PostgreSQL/Binary/Encoding/Builders.hs b/library/PostgreSQL/Binary/Encoding/Builders.hs
--- a/library/PostgreSQL/Binary/Encoding/Builders.hs
+++ b/library/PostgreSQL/Binary/Encoding/Builders.hs
@@ -342,6 +342,11 @@
 json_bytes =
   bytes
 
+{-# INLINE json_bytes_lazy #-}
+json_bytes_lazy :: N.ByteString -> Builder
+json_bytes_lazy =
+  lazyBytes
+
 {-# INLINE json_ast #-}
 json_ast :: R.Value -> Builder
 json_ast =
@@ -351,6 +356,11 @@
 jsonb_bytes :: ByteString -> Builder
 jsonb_bytes =
   mappend "\1" . bytes
+
+{-# INLINE jsonb_bytes_lazy #-}
+jsonb_bytes_lazy :: N.ByteString -> Builder
+jsonb_bytes_lazy =
+  mappend "\1" . lazyBytes
 
 {-# INLINE jsonb_ast #-}
 jsonb_ast :: R.Value -> Builder
diff --git a/postgresql-binary.cabal b/postgresql-binary.cabal
--- a/postgresql-binary.cabal
+++ b/postgresql-binary.cabal
@@ -1,7 +1,7 @@
 name:
   postgresql-binary
 version:
-  0.12.4.4
+  0.12.5
 synopsis:
   Encoders and decoders for the PostgreSQL's binary format
 description:
@@ -101,11 +101,7 @@
   default-language:
     Haskell2010
   build-depends:
-    aeson,
-    conversion ==1.*,
-    conversion-bytestring ==1.*,
-    conversion-text ==1.*,
-    json-ast ==0.3.*,
+    aeson >=2 && <3,
     network-ip >=0.2 && <1,
     postgresql-binary,
     postgresql-libpq ==0.9.*,
diff --git a/tasty/Main.hs b/tasty/Main.hs
--- a/tasty/Main.hs
+++ b/tasty/Main.hs
@@ -17,6 +17,7 @@
 import qualified Main.PTI as PTI
 import qualified Main.TextEncoder as TextEncoder
 import qualified Database.PostgreSQL.LibPQ as LibPQ
+import qualified Data.Text.Lazy as TextLazy
 import Main.Apx (Apx(..))
 
 
@@ -138,7 +139,7 @@
             ,
             primitiveRoundtrip "text_strict" Gens.text PTI.text A.text_strict B.text_strict
             ,
-            primitiveRoundtrip "text_lazy" (fmap convert Gens.text) PTI.text A.text_lazy B.text_lazy
+            primitiveRoundtrip "text_lazy" (fmap TextLazy.fromStrict Gens.text) PTI.text A.text_lazy B.text_lazy
             ,
             primitiveRoundtrip "bytea_strict" Gens.auto PTI.bytea A.bytea_strict B.bytea_strict
             ,
diff --git a/tasty/Main/Gens.hs b/tasty/Main/Gens.hs
--- a/tasty/Main/Gens.hs
+++ b/tasty/Main/Gens.hs
@@ -3,7 +3,6 @@
 import Main.Prelude hiding (assert, isRight, isLeft, choose)
 import Test.QuickCheck hiding (vector)
 import Test.QuickCheck.Instances
-import JSONAST
 import qualified Main.PTI as PTI
 import qualified Data.Scientific as Scientific
 import qualified Data.UUID as UUID
@@ -12,6 +11,8 @@
 import qualified PostgreSQL.Binary.Encoding as Encoder
 import qualified Data.Text as Text
 import qualified Data.Aeson as Aeson
+import qualified Data.Aeson.KeyMap as AesonKeyMap
+import qualified Data.Aeson.Key as AesonKey
 import qualified Network.IP.Addr as IPAddr
 
 
@@ -22,8 +23,19 @@
 auto =
   arbitrary
 
-json :: Gen JSON
-json =
+vector :: Gen a -> Gen (Vector a)
+vector element =
+  join $ Vector.replicateM <$> arbitrary <*> pure element
+
+hashMap :: (Eq a, Hashable a) => Gen a -> Gen b -> Gen (HashMap a b)
+hashMap key value =
+  fmap HashMap.fromList $ join $ replicateM <$> arbitrary <*> pure row
+  where
+    row =
+      (,) <$> key <*> value
+
+aeson :: Gen Aeson.Value
+aeson =
   byDepth 0
   where
     byDepth depth =
@@ -40,34 +52,27 @@
             freq =
               maxFreq - depth
         maxFreq =
-          6
+          4
         null =
-          pure JSON_Null
+          pure Aeson.Null
         bool =
-          fmap JSON_Bool arbitrary
+          fmap Aeson.Bool arbitrary
         number =
-          fmap JSON_Number arbitrary
+          fmap Aeson.Number arbitrary
         string =
-          fmap JSON_String text
+          fmap Aeson.String text
         array =
-          fmap JSON_Array (vector (byDepth (succ depth)))
+          fmap Aeson.Array (vector (byDepth (succ depth)))
         object =
-          fmap JSON_Object (hashMap text (byDepth (succ depth)))
-
-vector :: Gen a -> Gen (Vector a)
-vector element =
-  join $ Vector.replicateM <$> arbitrary <*> pure element
-
-hashMap :: (Eq a, Hashable a) => Gen a -> Gen b -> Gen (HashMap a b)
-hashMap key value =
-  fmap HashMap.fromList $ join $ replicateM <$> arbitrary <*> pure row
-  where
-    row =
-      (,) <$> key <*> value
-
-aeson :: Gen Aeson.Value
-aeson =
-  fmap unsafeCoerce json
+          Aeson.Object . AesonKeyMap.fromList <$> listOf pair
+          where
+            pair =
+              (,) <$> key <*> value
+              where
+                key =
+                  AesonKey.fromText <$> text
+                value =
+                  byDepth (succ depth)
 
 postgresInt :: (Bounded a, Ord a, Integral a, Arbitrary a) => Gen a
 postgresInt =
diff --git a/tasty/Main/IO.hs b/tasty/Main/IO.hs
--- a/tasty/Main/IO.hs
+++ b/tasty/Main/IO.hs
@@ -15,6 +15,8 @@
 import qualified PostgreSQL.Binary.Decoding as A
 import qualified PostgreSQL.Binary.Encoding as B
 import qualified Database.PostgreSQL.LibPQ as LibPQ
+import qualified Data.ByteString.Builder as ByteStringBuilder
+import qualified Data.ByteString.Lazy as ByteStringLazy
 
 
 textRoundtrip :: LibPQ.Oid -> TextEncoder.Encoder a -> (Bool -> A.Value a) -> a -> IO (Either Text a)
@@ -29,7 +31,7 @@
       [ Just ( oid , bytes , LibPQ.Text ) ]
       where
         bytes =
-          (convert . encoder) value
+          (ByteStringLazy.toStrict . ByteStringBuilder.toLazyByteString . encoder) value
 
 roundtrip :: LibPQ.Oid -> (Bool -> a -> B.Encoding) -> (Bool -> A.Value b) -> a -> IO (Either Text b)
 roundtrip oid encoder decoder value =
diff --git a/tasty/Main/Prelude.hs b/tasty/Main/Prelude.hs
--- a/tasty/Main/Prelude.hs
+++ b/tasty/Main/Prelude.hs
@@ -13,12 +13,6 @@
 -------------------------
 import Prelude as Exports hiding (assert, Data, fail, check)
 
--- conversion
--------------------------
-import Conversion as Exports
-import Conversion.Text ()
-import Conversion.ByteString ()
-
 -- custom
 -------------------------
 import qualified Data.ByteString.Lazy