diff --git a/src/json.ml b/src/json.ml
index af03ef53..6e9951bd 100644
--- a/src/json.ml
+++ b/src/json.ml
@@ -1,4 +1,3 @@
-open Types
 open Api_types
 open Crypto
 
@@ -19,6 +18,12 @@ module ErrorDetail = struct
     |> Jsont.Object.finish
 end
 
+module Amount = struct
+  include Amount
+
+  let jsont = Jsont.of_of_string ~kind:"Amount" of_string ~enc:to_string
+end
+
 module Timestamp = struct
   open Timestamp
 
diff --git a/src/types.ml b/src/types.ml
deleted file mode 100644
index 3c20c4db..00000000
--- a/src/types.ml
+++ /dev/null
@@ -1,5 +0,0 @@
-module Amount = struct
-  include Amount
-
-  let jsont = Jsont.of_of_string ~kind:"Amount" of_string ~enc:to_string
-end
diff --git a/test/test.ml b/test/test.ml
index ed024f22..91edf657 100644
--- a/test/test.ml
+++ b/test/test.ml
@@ -28,10 +28,10 @@ let () =
   ()
 
 let () =
-  let open Types.Amount in
+  let open Amount in
   let v =
-    Amount.make ~sign:(Some Amount.Sign_plus) ~currency:"EUR"
-      ~value:(Int64.of_int 25) ~fraction:(Int32.of_int 678)
+    make ~sign:(Some Sign_plus) ~currency:"EUR" ~value:(Int64.of_int 25)
+      ~fraction:(Int32.of_int 678)
     |> Result.get_ok
   in
   let s = to_string v in