diff --git a/contrib/pyln-client/pyln/client/plugin.py b/contrib/pyln-client/pyln/client/plugin.py
index 5d3095e7e..a730fc449 100644
--- a/contrib/pyln-client/pyln/client/plugin.py
+++ b/contrib/pyln-client/pyln/client/plugin.py
@@ -223,6 +223,7 @@ class Plugin(object):
         }
 
         self.options: Dict[str, Dict[str, Any]] = {}
+        self.notification_topics: List[str] = []
 
         def convert_featurebits(
                 bits: Optional[Union[int, str, bytes]]) -> Optional[str]:
@@ -420,6 +421,11 @@ class Plugin(object):
         self.add_option(name, None, description, opt_type="flag",
                         deprecated=deprecated)
 
+    def add_notification_topic(self, topic: str):
+        """Announce that the plugin will emit notifications for the topic.
+        """
+        self.notification_topics.append(topic)
+
     def get_option(self, name: str) -> str:
         if name not in self.options:
             raise ValueError("No option with name {} registered".format(name))
@@ -898,6 +904,9 @@ class Plugin(object):
             'subscriptions': list(self.subscriptions.keys()),
             'hooks': hooks,
             'dynamic': self.dynamic,
+            'notifications': [
+                {"method": name} for name in self.notification_topics
+            ],
         }
 
         # Compact the features a bit, not important.
diff --git a/lightningd/notification.c b/lightningd/notification.c
index 7cb2ebea9..bcd4491d0 100644
--- a/lightningd/notification.c
+++ b/lightningd/notification.c
@@ -18,12 +18,19 @@ static struct notification *find_notification_by_topic(const char* topic)
 	return NULL;
 }
 
-bool notifications_have_topic(const char *topic)
+bool notifications_have_topic(const struct plugins *plugins, const char *topic)
 {
 	struct notification *noti = find_notification_by_topic(topic);
 	if (noti)
 		return true;
 
+	/* Some plugin at some point announced it'd be emitting
+	 * notifications to this topic. We don't care if it died, just
+	 * that it was a valid topic at some point in time. */
+	for (size_t i=0; i<tal_count(plugins->notification_topics); i++)
+		if (streq(plugins->notification_topics[i], topic))
+			return true;
+
 	return false;
 }
 
diff --git a/lightningd/notification.h b/lightningd/notification.h
index 8ad8e9de0..6736db912 100644
--- a/lightningd/notification.h
+++ b/lightningd/notification.h
@@ -25,7 +25,7 @@
 struct onionreply;
 struct wally_psbt;
 
-bool notifications_have_topic(const char *topic);
+bool notifications_have_topic(const struct plugins *plugins, const char *topic);
 
 struct notification {
 	const char *topic;
diff --git a/lightningd/plugin.c b/lightningd/plugin.c
index 5c68d86cd..ac0700fc5 100644
--- a/lightningd/plugin.c
+++ b/lightningd/plugin.c
@@ -76,6 +76,7 @@ struct plugins *plugins_new(const tal_t *ctx, struct log_book *log_book,
 	p->startup = true;
 	p->json_cmds = tal_arr(p, struct command *, 0);
 	p->blacklist = tal_arr(p, const char *, 0);
+	p->notification_topics = tal_arr(p, const char *, 0);
 	p->shutdown = false;
 	p->plugin_idx = 0;
 #if DEVELOPER
@@ -103,6 +104,25 @@ void plugins_free(struct plugins *plugins)
 	tal_free(plugins);
 }
 
+/* Check that all the plugin's subscriptions are actually for known
+ * notification topics. Emit a warning if that's not the case, but
+ * don't kill the plugin. */
+static void plugin_check_subscriptions(struct plugins *plugins,
+				       struct plugin *plugin)
+{
+	if (plugin->subscriptions == NULL)
+		return;
+
+	for (size_t i = 0; i < tal_count(plugin->subscriptions); i++) {
+		const char *topic = plugin->subscriptions[i];
+		if (!notifications_have_topic(plugins, topic))
+			log_unusual(
+			    plugin->log,
+			    "topic '%s' is not a known notification topic",
+			    topic);
+	}
+}
+
 /* Once they've all replied with their manifests, we can order them. */
 static void check_plugins_manifests(struct plugins *plugins)
 {
@@ -1136,14 +1156,12 @@ static const char *plugin_subscriptions_add(struct plugin *plugin,
 					json_tok_full_len(s),
 					json_tok_full(buffer, s));
 		}
+
+		/* We add all subscriptions while parsing the
+		 * manifest, without checking that they exist, since
+		 * later plugins may also emit notifications of custom
+		 * types that we don't know about yet. */
 		topic = json_strdup(plugin, plugin->buffer, s);
-
-		if (!notifications_have_topic(topic)) {
-			return tal_fmt(
-			    plugin,
-			    "topic '%s' is not a known notification topic", topic);
-		}
-
 		tal_arr_expand(&plugin->subscriptions, topic);
 	}
 	return NULL;
@@ -1338,6 +1356,8 @@ static const char *plugin_parse_getmanifest_response(const char *buffer,
 	if (!err)
 		err = plugin_add_params(plugin);
 
+	plugin_check_subscriptions(plugin->plugins, plugin);
+
 	plugin->plugin_state = NEEDS_INIT;
 	return err;
 }
diff --git a/lightningd/plugin.h b/lightningd/plugin.h
index f7954e568..27e2ee777 100644
--- a/lightningd/plugin.h
+++ b/lightningd/plugin.h
@@ -128,6 +128,10 @@ struct plugins {
 	/* Whether builtin plugins should be overridden as unimportant.  */
 	bool dev_builtin_plugins_unimportant;
 #endif /* DEVELOPER */
+
+	/* Notification topics that plugins have registered with us
+	 * and that other plugins may subscribe to. */
+	const char **notification_topics;
 };
 
 /* The value of a plugin option, which can have different types.
diff --git a/tests/plugins/custom_notifications.py b/tests/plugins/custom_notifications.py
new file mode 100755
index 000000000..9b32aa45e
--- /dev/null
+++ b/tests/plugins/custom_notifications.py
@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+from pyln.client import Plugin
+
+
+plugin = Plugin()
+
+
+@plugin.subscribe("custom")
+def on_custom_notification(val, plugin, **kwargs):
+    plugin.log("Got a custom notification {}".format(val))
+
+
+@plugin.method("emit")
+def emit(plugin):
+    """Emit a simple string notification to topic "custom"
+    """
+    plugin.notify("custom", "Hello world")
+
+
+plugin.add_notification_topic("custom")
+plugin.run()
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index 6ea840e9d..308710c79 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -2402,3 +2402,13 @@ def test_self_disable(node_factory):
     # Also works with dynamic load attempts
     with pytest.raises(RpcError, match="Disabled via selfdisable option"):
         l1.rpc.plugin_start(p2, selfdisable=True)
+
+
+@pytest.mark.xfail(strict=True)
+def test_custom_notification_topics(node_factory):
+    plugin = os.path.join(
+        os.path.dirname(__file__), "plugins", "custom_notifications.py"
+    )
+    l1 = node_factory.get_node(options={'plugin': plugin})
+    l1.rpc.emit()
+    l1.daemon.wait_for_log(r'Got a custom notification Hello world')