diff --git a/meson.build b/meson.build
index 1465fa3e..f17ab7ef 100644
--- a/meson.build
+++ b/meson.build
@@ -181,7 +181,7 @@ executable(
   'spawn.c', 'spawn.h',
   'tokenize.c', 'tokenize.h',
   'url-mode.c', 'url-mode.h',
-  'user-notification.h',
+  'user-notification.c', 'user-notification.h',
   'wayland.c', 'wayland.h',
   wl_proto_src + wl_proto_headers, version,
   dependencies: [math, threads, libepoll, pixman, wayland_client, wayland_cursor, xkb, fontconfig,
diff --git a/user-notification.c b/user-notification.c
new file mode 100644
index 00000000..497aa08c
--- /dev/null
+++ b/user-notification.c
@@ -0,0 +1,38 @@
+#include "user-notification.h"
+#include <stdio.h>
+#include <stdarg.h>
+
+static bool
+user_notification_add_va(user_notifications_t *notifications,
+                         enum user_notification_kind kind, const char *fmt,
+                         va_list ap)
+{
+    va_list ap2;
+    va_copy(ap2, ap);
+    int cnt = vsnprintf(NULL, 0, fmt, ap2);
+    va_end(ap2);
+
+    if (cnt < 0)
+        return false;
+
+    char *text = malloc(cnt + 1);
+    vsnprintf(text, cnt + 1, fmt, ap);
+
+    struct user_notification not = {
+        .kind = kind,
+        .text = text,
+    };
+    tll_push_back(*notifications, not);
+    return true;
+}
+
+bool
+user_notification_add(user_notifications_t *notifications,
+                      enum user_notification_kind kind, const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    bool ret = user_notification_add_va(notifications, kind, fmt, ap);
+    va_end(ap);
+    return ret;
+}
diff --git a/user-notification.h b/user-notification.h
index f184871e..507c1791 100644
--- a/user-notification.h
+++ b/user-notification.h
@@ -1,7 +1,10 @@
 #pragma once
 
+#include <stdbool.h>
 #include <tllist.h>
 
+#include "macros.h"
+
 enum user_notification_kind {
     USER_NOTIFICATION_DEPRECATED,
     USER_NOTIFICATION_WARNING,
@@ -22,3 +25,7 @@ user_notifications_free(user_notifications_t *notifications)
         free(it->item.text);
     tll_free(*notifications);
 }
+
+bool user_notification_add(user_notifications_t *notifications,
+                           enum user_notification_kind kind,
+                           const char *fmt, ...) PRINTF(3);