main.py

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

app = FastAPI()

origins = ['http://localhost:3000', 'http://127.0.0.1:3000',
           'https://localhost:3000', 'https://127.0.0.1:3000', 'https://codepen.io/'] 

app.add_middleware(
    CORSMiddleware,
    allow_origins=['*']
)

@app.get("/")
def read_root():
    return {"message": "Hello World"}
    
@app.get("/api/python")
def hello_python():
    return {"message": "Hello Python"}