diff --git a/caisar.opam b/caisar.opam
index adce2f75393812bb747e7859ea7eec9e2fba2a87..d3656036486853eb3baffe0deb5389a92dddb0a7 100644
--- a/caisar.opam
+++ b/caisar.opam
@@ -12,6 +12,7 @@ depends: [
   "ppx_deriving" {>= "5.1"}
   "yojson" {>= "1.7.0"}
   "menhirLib" {>= "20210310"}
+  "ppx_deriving_yojson" {>= "3.6.1"}
   "odoc" {with-doc}
 ]
 build: [
diff --git a/dune-project b/dune-project
index 908fc1e0ee52347e4c0263fe8eca540d93ef8e9d..d165345231b0a3b858084fe81e6931a5723a10f4 100644
--- a/dune-project
+++ b/dune-project
@@ -19,5 +19,6 @@
    (ppx_deriving (>= 5.1))
    (yojson (>= 1.7.0))
    (menhirLib (>= 20210310))
+   (ppx_deriving_yojson (>= 3.6.1))
   )
 )