Only if using the Stripe PaymentIntent integration
REDIS_URL
Session store; omit to fall back to in-memory
COMMERCE_BACKEND
icommerce for real order execution, else stub
In-memory sessions do not survive a restart or a scale-out. A deployment with more than one
replica, or any deployment you care about, needs REDIS_URL set — otherwise a checkout session
created on one pod is invisible to the next request.