Example FastAPI backend with CORS Middleware

app.py

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from pydantic import BaseModel

app = FastAPI()

app.add_middleware(
    # We add the middleware here
    CORSMiddleware,
    # These are the options we give the middleware and they map easily to their
    # associated CORS headers
    allow_origins=['http://localhost:63342', 'http://localhost'],
    allow_methods=['GET', 'POST'],
    allow_headers=['X-My-Custom-Header']
)


class Item(BaseModel):
    name: str


@app.get('/')
async def root():
    return dict(message="Hello")


@app.options('/items')
@app.get('/items')
async def list_items():
    return [
        Item(name="One"),
        Item(name="Two"),
        Item(name="Three"),
    ]