diff --git a/examples/api/main.py b/examples/api/main.py
index 1542b1740..90f2f138b 100644
--- a/examples/api/main.py
+++ b/examples/api/main.py
@@ -23,7 +23,10 @@
 
 
 from pydantic import BaseModel
-
+from fastapi.exceptions import RequestValidationError
+from fastapi.responses import JSONResponse
+from tools.normalizer.en import normalizer_en_nemo_text
+from tools.normalizer.zh import normalizer_zh_tn
 
 logger = get_logger("Command")
 
@@ -35,14 +38,23 @@ async def startup_event():
     global chat
 
     chat = ChatTTS.Chat(get_logger("ChatTTS"))
+    chat.normalizer.register("en", normalizer_en_nemo_text())
+    chat.normalizer.register("zh", normalizer_zh_tn())
+    
     logger.info("Initializing ChatTTS...")
-    if chat.load():
+    if chat.load(source="huggingface"):
         logger.info("Models loaded successfully.")
     else:
         logger.error("Models load failed.")
         sys.exit(1)
 
 
+@app.exception_handler(RequestValidationError)
+async def validation_exception_handler(request, exc: RequestValidationError):
+    logger.error(f"Validation error: {exc.errors()}")
+    return JSONResponse(status_code=422, content={"detail": exc.errors()})
+
+
 class ChatTTSParams(BaseModel):
     text: list[str]
     stream: bool = False
@@ -52,7 +64,7 @@ class ChatTTSParams(BaseModel):
     use_decoder: bool = True
     do_text_normalization: bool = True
     do_homophone_replacement: bool = False
-    params_refine_text: ChatTTS.Chat.RefineTextParams
+    params_refine_text: ChatTTS.Chat.RefineTextParams = None
     params_infer_code: ChatTTS.Chat.InferCodeParams