diff --git a/plugins/libplugin.c b/plugins/libplugin.c
index 6687fe838..f3c70d03e 100644
--- a/plugins/libplugin.c
+++ b/plugins/libplugin.c
@@ -325,6 +325,7 @@ struct out_req *
 jsonrpc_request_start_(struct plugin *plugin, struct command *cmd,
 		       const char *method,
 		       const char *id_prefix,
+		       const char *filter,
 		       struct command_result *(*cb)(struct command *command,
 						    const char *buf,
 						    const jsmntok_t *result,
@@ -355,6 +356,12 @@ jsonrpc_request_start_(struct plugin *plugin, struct command *cmd,
 	json_add_string(out->js, "jsonrpc", "2.0");
 	json_add_id(out->js, out->id);
 	json_add_string(out->js, "method", method);
+	if (filter) {
+		/* This is raw JSON, so paste, don't escape! */
+		size_t len = strlen(filter);
+		char *p = json_out_member_direct(out->js->jout, "filter", len);
+		memcpy(p, filter, len);
+	}
 	if (out->errcb)
 		json_object_start(out->js, "params");
 
diff --git a/plugins/libplugin.h b/plugins/libplugin.h
index 331f45d26..07e959d3c 100644
--- a/plugins/libplugin.h
+++ b/plugins/libplugin.h
@@ -103,6 +103,7 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin,
 				       struct command *cmd,
 				       const char *method,
 				       const char *id_prefix,
+				       const char *filter,
 				       struct command_result *(*cb)(struct command *command,
 								    const char *buf,
 								    const jsmntok_t *result,
@@ -117,7 +118,7 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin,
  * "error" members. */
 #define jsonrpc_request_start(plugin, cmd, method, cb, errcb, arg)	\
 	jsonrpc_request_start_((plugin), (cmd), (method),		\
-		     json_id_prefix(tmpctx, (cmd)),			\
+		     json_id_prefix(tmpctx, (cmd)), NULL,		\
 		     typesafe_cb_preargs(struct command_result *, void *, \
 					 (cb), (arg),			\
 					 struct command *command,	\
@@ -130,11 +131,25 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin,
 					 const jsmntok_t *result),	\
 		     (arg))
 
+#define jsonrpc_request_with_filter_start(plugin, cmd, method, filter, cb, errcb, arg) \
+	jsonrpc_request_start_((plugin), (cmd), (method),		\
+		     json_id_prefix(tmpctx, (cmd)), (filter),		\
+		     typesafe_cb_preargs(struct command_result *, void *, \
+					 (cb), (arg),			\
+					 struct command *command,	\
+					 const char *buf,		\
+					 const jsmntok_t *result),	\
+		     typesafe_cb_preargs(struct command_result *, void *, \
+					 (errcb), (arg),		\
+					 struct command *command,	\
+					 const char *buf,		\
+					 const jsmntok_t *result),	\
+		     (arg))
 
 /* This variant has callbacks received whole obj, not "result" or
  * "error" members.  It also doesn't start params{}. */
 #define jsonrpc_request_whole_object_start(plugin, cmd, method, id_prefix, cb, arg) \
-	jsonrpc_request_start_((plugin), (cmd), (method), (id_prefix),	\
+	jsonrpc_request_start_((plugin), (cmd), (method), (id_prefix), NULL, \
 			       typesafe_cb_preargs(struct command_result *, void *, \
 						   (cb), (arg),		\
 						   struct command *command, \
diff --git a/plugins/test/run-route-calc.c b/plugins/test/run-route-calc.c
index 5cee7ad8e..ee4a1ab74 100644
--- a/plugins/test/run-route-calc.c
+++ b/plugins/test/run-route-calc.c
@@ -228,6 +228,7 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin UNNEEDED,
 				       struct command *cmd UNNEEDED,
 				       const char *method UNNEEDED,
 				       const char *id_prefix UNNEEDED,
+				       const char *filter UNNEEDED,
 				       struct command_result *(*cb)(struct command *command UNNEEDED,
 								    const char *buf UNNEEDED,
 								    const jsmntok_t *result UNNEEDED,
diff --git a/plugins/test/run-route-overlong.c b/plugins/test/run-route-overlong.c
index 3e55dc4cb..8f9ce9bde 100644
--- a/plugins/test/run-route-overlong.c
+++ b/plugins/test/run-route-overlong.c
@@ -225,6 +225,7 @@ struct out_req *jsonrpc_request_start_(struct plugin *plugin UNNEEDED,
 				       struct command *cmd UNNEEDED,
 				       const char *method UNNEEDED,
 				       const char *id_prefix UNNEEDED,
+				       const char *filter UNNEEDED,
 				       struct command_result *(*cb)(struct command *command UNNEEDED,
 								    const char *buf UNNEEDED,
 								    const jsmntok_t *result UNNEEDED,