Environment variables
NEXTAUTH_URL​
When deploying to production, set the NEXTAUTH_URL environment variable to the canonical URL of your site.
NEXTAUTH_URL=https://example.com
If your Next.js application uses a custom base path, specify the route to the API endpoint in full.
e.g. NEXTAUTH_URL=https://example.com/custom-route/api/auth
Using System Environment Variables we automatically detect when you deploy to Vercel so you don't have to define this variable. Make sure Automatically expose System Environment Variables is checked in your Project Settings.
NEXTAUTH_SECRET​
Used to encrypt the NextAuth.js JWT, and to hash email verification tokens. This is the default value for the secret option. The secret option might be removed in the future in favor of this.
If you are using Middleware this environment variable must be set.
NEXTAUTH_URL_INTERNAL​
If provided, server-side calls will use this instead of NEXTAUTH_URL. Useful in environments when the server doesn't have access to the canonical URL of your site. Defaults to NEXTAUTH_URL.
NEXTAUTH_URL_INTERNAL=http://10.240.8.16