diff --git a/dune-project b/dune-project
index 15e8b7f2..5c8bb4be 100644
--- a/dune-project
+++ b/dune-project
@@ -29,6 +29,7 @@
   atomic
   hmap
   thread-local-storage
+  (yojson (>= 1.6))
   camlzip
   (mtime
    (>= 2.0))
diff --git a/imandrakit.opam b/imandrakit.opam
index 8fbb5574..5580c3ef 100644
--- a/imandrakit.opam
+++ b/imandrakit.opam
@@ -21,6 +21,7 @@ depends: [
   "atomic"
   "hmap"
   "thread-local-storage"
+  "yojson" {>= "1.6"}
   "camlzip"
   "mtime" {>= "2.0"}
   "zarith" {>= "1.12"}