diff --git a/modules/script_callbacks.py b/modules/script_callbacks.py
index 6ea58d616..d8aa6f008 100644
--- a/modules/script_callbacks.py
+++ b/modules/script_callbacks.py
@@ -3,6 +3,8 @@ import traceback
 from collections import namedtuple
 import inspect
 
+from fastapi import FastAPI
+from gradio import Blocks
 
 def report_exception(c, job):
     print(f"Error executing callback {job} for {c.script}", file=sys.stderr)
@@ -25,6 +27,7 @@ class ImageSaveParams:
 
 
 ScriptCallback = namedtuple("ScriptCallback", ["script", "callback"])
+callbacks_app_started = []
 callbacks_model_loaded = []
 callbacks_ui_tabs = []
 callbacks_ui_settings = []
@@ -40,6 +43,14 @@ def clear_callbacks():
     callbacks_image_saved.clear()
 
 
+def app_started_callback(demo: Blocks, app: FastAPI):
+    for c in callbacks_app_started:
+        try:
+            c.callback(demo, app)
+        except Exception:
+            report_exception(c, 'app_started_callback')
+
+
 def model_loaded_callback(sd_model):
     for c in callbacks_model_loaded:
         try:
@@ -91,6 +102,12 @@ def add_callback(callbacks, fun):
     callbacks.append(ScriptCallback(filename, fun))
 
 
+def on_app_started(callback):
+    """register a function to be called when the webui started, the gradio `Block` component and
+    fastapi `FastAPI` object are passed as the arguments"""
+    add_callback(callbacks_app_started, callback)
+
+
 def on_model_loaded(callback):
     """register a function to be called when the stable diffusion model is created; the model is
     passed as an argument"""
diff --git a/webui.py b/webui.py
index 6ff95dc47..8d8479f1d 100644
--- a/webui.py
+++ b/webui.py
@@ -23,6 +23,7 @@ import modules.sd_hijack
 import modules.sd_models
 import modules.shared as shared
 import modules.txt2img
+import modules.script_callbacks
 
 import modules.ui
 from modules import devices
@@ -140,6 +141,8 @@ def webui():
         if launch_api:
             create_api(app)
 
+        modules.script_callbacks.app_started_callback(demo, app)
+
         wait_on_server(demo)
 
         sd_samplers.set_samplers()