diff --git a/modules/api/api.py b/modules/api/api.py
index f0a68c672..45c5c5077 100644
--- a/modules/api/api.py
+++ b/modules/api/api.py
@@ -251,14 +251,10 @@ class Api:
         self.default_script_arg_txt2img = []
         self.default_script_arg_img2img = []
 
-        script_runner = scripts.scripts_img2img
-        if not script_runner.scripts:
-            script_runner.initialize_scripts(True)
-            ui.create_ui()
-        if not self.default_script_arg_txt2img:
-            self.default_script_arg_txt2img = self.init_default_script_args(script_runner)
-        if not self.default_script_arg_img2img:
-            self.default_script_arg_img2img = self.init_default_script_args(script_runner)
+        self.txt2img_script_arg_init_lock = Lock()
+        self.img2img_script_arg_init_lock = Lock()
+
+
 
     def add_api_route(self, path: str, endpoint, **kwargs):
         if shared.cmd_opts.api_auth:
@@ -348,6 +344,12 @@ class Api:
         task_id = txt2imgreq.force_task_id or create_task_id("txt2img")
 
         script_runner = scripts.scripts_txt2img
+        with self.txt2img_script_arg_init_lock:
+            if not script_runner.scripts:
+                script_runner.initialize_scripts(False)
+                ui.create_ui()
+            if not self.default_script_arg_txt2img:
+                self.default_script_arg_txt2img = self.init_default_script_args(script_runner)
         selectable_scripts, selectable_script_idx = self.get_selectable_script(txt2imgreq.script_name, script_runner)
 
         populate = txt2imgreq.copy(update={  # Override __init__ params
@@ -407,6 +409,12 @@ class Api:
             mask = decode_base64_to_image(mask)
 
         script_runner = scripts.scripts_img2img
+        with self.img2img_script_arg_init_lock:
+            if not script_runner.scripts:
+                script_runner.initialize_scripts(True)
+                ui.create_ui()
+            if not self.default_script_arg_img2img:
+                self.default_script_arg_img2img = self.init_default_script_args(script_runner)
         selectable_scripts, selectable_script_idx = self.get_selectable_script(img2imgreq.script_name, script_runner)
 
         populate = img2imgreq.copy(update={  # Override __init__ params