diff --git a/python/pyproject.toml b/python/pyproject.toml
index 116ba9c9849..800ce0837e2 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -21,7 +21,7 @@ dependencies = [
 
 [project.optional-dependencies]
 runtime_common = ["aiohttp", "decord", "fastapi", "hf_transfer", "huggingface_hub", "interegular",
-    "packaging", "pillow", "psutil", "pydantic", "python-multipart",
+    "orjson", "packaging", "pillow", "psutil", "pydantic", "python-multipart",
     "torchao", "uvicorn", "uvloop", "zmq",
     "outlines>=0.0.44", "modelscope"]
 # xpu is not enabled in public vllm and torch whl,
diff --git a/python/sglang/srt/openai_api/adapter.py b/python/sglang/srt/openai_api/adapter.py
index 4e70546dfdd..b4727dfd7b6 100644
--- a/python/sglang/srt/openai_api/adapter.py
+++ b/python/sglang/srt/openai_api/adapter.py
@@ -25,7 +25,7 @@
 from typing import Dict, List
 
 from fastapi import HTTPException, Request, UploadFile
-from fastapi.responses import JSONResponse, StreamingResponse
+from fastapi.responses import ORJSONResponse, StreamingResponse
 from pydantic import ValidationError
 
 try:
@@ -101,7 +101,7 @@ def create_error_response(
     status_code: HTTPStatus = HTTPStatus.BAD_REQUEST,
 ):
     error = ErrorResponse(message=message, type=err_type, code=status_code.value)
-    return JSONResponse(content=error.model_dump(), status_code=error.code)
+    return ORJSONResponse(content=error.model_dump(), status_code=error.code)
 
 
 def create_streaming_error_response(
diff --git a/python/sglang/srt/server.py b/python/sglang/srt/server.py
index f0b7abbe3e9..8f851c757f1 100644
--- a/python/sglang/srt/server.py
+++ b/python/sglang/srt/server.py
@@ -40,7 +40,7 @@
 import uvloop
 from fastapi import FastAPI, File, Form, Request, UploadFile
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import JSONResponse, Response, StreamingResponse
+from fastapi.responses import ORJSONResponse, Response, StreamingResponse
 
 from sglang.lang.backend.runtime_endpoint import RuntimeEndpoint
 from sglang.srt.hf_transformers_utils import get_tokenizer
@@ -176,12 +176,12 @@ async def update_weights(obj: UpdateWeightReqInput, request: Request):
     success, message = await tokenizer_manager.update_weights(obj, request)
     content = {"success": success, "message": message}
     if success:
-        return JSONResponse(
+        return ORJSONResponse(
             content,
             status_code=HTTPStatus.OK,
         )
     else:
-        return JSONResponse(
+        return ORJSONResponse(
             content,
             status_code=HTTPStatus.BAD_REQUEST,
         )
@@ -211,7 +211,7 @@ async def stream_results():
             ret = await tokenizer_manager.generate_request(obj, request).__anext__()
             return ret
         except ValueError as e:
-            return JSONResponse(
+            return ORJSONResponse(
                 {"error": {"message": str(e)}}, status_code=HTTPStatus.BAD_REQUEST
             )
 
@@ -226,7 +226,7 @@ async def encode_request(obj: EmbeddingReqInput, request: Request):
         ret = await tokenizer_manager.generate_request(obj, request).__anext__()
         return ret
     except ValueError as e:
-        return JSONResponse(
+        return ORJSONResponse(
             {"error": {"message": str(e)}}, status_code=HTTPStatus.BAD_REQUEST
         )
 
@@ -241,7 +241,7 @@ async def judge_request(obj: RewardReqInput, request: Request):
         ret = await tokenizer_manager.generate_request(obj, request).__anext__()
         return ret
     except ValueError as e:
-        return JSONResponse(
+        return ORJSONResponse(
             {"error": {"message": str(e)}}, status_code=HTTPStatus.BAD_REQUEST
         )
 
diff --git a/python/sglang/srt/utils.py b/python/sglang/srt/utils.py
index c5aecb73938..0f5401c8e9e 100644
--- a/python/sglang/srt/utils.py
+++ b/python/sglang/srt/utils.py
@@ -35,7 +35,7 @@
 import requests
 import torch
 import torch.distributed as dist
-from fastapi.responses import JSONResponse
+from fastapi.responses import ORJSONResponse
 from packaging import version as pkg_version
 from torch import nn
 from torch.profiler import ProfilerActivity, profile, record_function
@@ -566,7 +566,7 @@ async def authentication(request, call_next):
         if request.url.path.startswith("/health"):
             return await call_next(request)
         if request.headers.get("Authorization") != "Bearer " + api_key:
-            return JSONResponse(content={"error": "Unauthorized"}, status_code=401)
+            return ORJSONResponse(content={"error": "Unauthorized"}, status_code=401)
         return await call_next(request)