👀 Views: 34 💬 Answers: 1 📅 Created: 2025-06-06

fastapi cors http-status-403 web-development Python

I'm currently developing an API using FastAPI and I need to enable CORS for my frontend application, which is hosted on a different domain. Despite configuring CORS, I'm consistently receiving a 403 Forbidden response when trying to access the API endpoints from the frontend. I've tried using `fastapi.middleware.cors.CORSMiddleware` and added the allowed origins, but it doesn't seem to be working as expected. Here's the relevant portion of my code where I set up the FastAPI application: ```python from fastapi import FastAPI from fastapi.middleware.cors import CORSMiddleware app = FastAPI() app.add_middleware( CORSMiddleware, allow_origins=["https://myfrontend.com"], # my frontend domain allow_credentials=True, allow_methods=["*"], # allow all methods allow_headers=["*"], # allow all headers ) @app.get("/items/{item_id}") async def read_item(item_id: int): return {"item_id": item_id} ``` I've ensured that the frontend is correctly making requests to the right API URL, and I have no typos in the URL. Also, I checked the network tab in the browser and confirmed that the request is being sent to the correct endpoint, but the response headers indicate that it's being blocked due to CORS policy. In addition, I've tried explicitly setting `allow_methods` and `allow_headers` to specific values instead of using `"*"`, but that didn't resolve the scenario either. I've also verified that the API is running on the same server and port, but accessed through different domains in development (localhost for API and a separate localhost for frontend). Could there be any other configurations or pitfalls I might be missing that lead to this 403 behavior? Any guidance would be greatly appreciated!