diff --git a/include/types/applet.h b/include/types/applet.h
index 6b46f4945..13817b22a 100644
--- a/include/types/applet.h
+++ b/include/types/applet.h
@@ -24,6 +24,8 @@
 
 #include <types/hlua.h>
 #include <types/obj_type.h>
+#include <types/proxy.h>
+#include <types/stream.h>
 #include <common/chunk.h>
 #include <common/config.h>
 
@@ -34,6 +36,8 @@ struct applet {
 	enum obj_type obj_type;            /* object type = OBJ_TYPE_APPLET */
 	/* 3 unused bytes here */
 	char *name;                        /* applet's name to report in logs */
+	int (*init)(struct appctx *, struct proxy *px, struct stream *strm);   /* callback to init ressources, may be NULL.
+	                                     expect 1 if ok, 0 if an error occurs, -1 if miss data. */
 	void (*fct)(struct appctx *);      /* internal I/O handler, may never be NULL */
 	void (*release)(struct appctx *);  /* callback to release resources, may be NULL */
 };