FastAPI has a
built-in middleware for managing CORS, which can be added to the application instance. To enable it, import
CORSMiddleware from fastapi.middleware.cors and add it to your
FastAPI app using the
.add_middleware() method. You need to specify parameters like
allow_origins (a list of origins that are allowed),
allow_credentials (whether cookies can be supported),
allow_methods (HTTP methods allowed), and
allow_headers (which HTTP headers are permitted). Here’s an example:
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
app = FastAPI()
origins = ["http://localhost:3000"]
app.add_middleware(
CORSMiddleware,
allow_origins=origins,
allow_credentials=True,
allow_methods=["*"],
allow_headers=["*"],
)
@app.get("/")
async def main():
return {"message": "Hello World"}?
