Although I am returning a sorted dictionary by value, FastAPI response is not sorted. I'm using python: 3.8.10 fastapi: 0.95.2 This is my endpoint: @classifier_router.post("/groupClassifier") async def group_classifier( # current_user: User = Depends(get_current_user), group_id: str = Query(default="1069302375", description=GROUP_ID_DESC), starttime: Union[datetime , None] = DEFAULT_START_TIME, endtime: Union[datetime , None] = DEFAULT_END_TIME): result = handler.group_classifier( [group_id], starttime, endtime) if result==None: raise HTTPException( status_code=500 ) else: return result Result which returned in swagger: { "class_scores": { "1": 34.8, "2": 22.1, "3": 16.9, "4": 7.8, "5": 26, "6": 23.6 } } Continue reading...