SubscriptionBillingAttempt - Failures on free orders

[brett_single]

Our use case involves yearly subscriptions with free products shipped out to members on a monthly basis. Our process was to make a billing cycle edit for the month, add the free item along with free shipping, remove the original product, and commit the changes. We then submit a billing attempt for the $0 billing cycle, which in turn creates the $0 order in shopify.

Starting May 1, the free billing attempts began failing with error code "amount_too_small" and message "Amount must be at least $0.50 usd". Nothing about our process has changed in months. We have had no issues submitting these $0 billing attempts until now. It seems like something has changed in shopify's contract billing system that causes it to actually trigger a charge instead of skipping charging the user's payment method on $0 orders.

[moshbray]

this seems to be a new change as of May 1. Shopify is now enforcing a $0.50 USD minimum on billing attempts, even for $0 orders that previously went through just fine.

It’s likely part of a recent update to Shopify’s contract billing system, possibly to prevent misuse or clarify intent with the payment processor.

We’re looking at alternatives like skipping billing attempts entirely, or using draft orders to fulfill $0 cycles outside the subscription flow.