diff --git a/opam b/opam
index 17f8645f..2dbec1b2 100644
--- a/opam
+++ b/opam
@@ -30,6 +30,7 @@ depends: [
   "yojson" {>= "1.6.0"}
   "resource-pooling" {>= "1.0" & < "2.0"}
   "cohttp-lwt-unix"
+  "js_of_ocaml" {>= "5.5.0"}
   "re" {>= "1.7.2"}
 ]
 depexts: [