.env variables is an ampty string

i have to pass a .env variable to a Stripe object, but i´m getting the following error:

Uncaught (in promise) IntegrationError: Please call Stripe() with your publishable key. You used an empty string.

Here is the code

import Stripe from "stripe";

const stripe = new Stripe(process.env.NEXT_PUBLIC_STRIPE_SECRET_KEY);

.env

>Solution :

In Next.js you should declare your environment variables in a .env.local file.
For more informations check the official docs.