app.py

import os
import streamlit as st
from streamlit_cookies_manager import EncryptedCookieManager

# This should be on top of your script
cookies = EncryptedCookieManager(
    # This prefix will get added to all your cookie names.
    # This way you can run your app on Streamlit Cloud without cookie name clashes with other apps.
    prefix="ktosiek/streamlit-cookies-manager/",
    # You should really setup a long COOKIES_PASSWORD secret if you're running on Streamlit Cloud.
    password=os.environ.get("COOKIES_PASSWORD", "My secret password"),
)
if not cookies.ready():
    # Wait for the component to load and send us current cookies.
    st.stop()

st.write("Current cookies:", cookies)
value = st.text_input("New value for a cookie")
if st.button("Change the cookie"):
    cookies['a-cookie'] = value  # This will get saved on next rerun
    if st.button("No really, change it now"):
        cookies.save()  # Force saving the cookies now, without a rerun