Assigns multiple customers to a plan in a single request. This is useful for:
Each customer is processed independently. If a customer fails (e.g., not found, already subscribed), other customers will still be processed. The response includes both succeeded and failed arrays so you can handle partial failures.
Use skip_invoice: true when migrating customers who have already paid externally — the subscription is created without generating an invoice.
Array of customer keys to assign to the plan
["cust_001", "cust_002", "cust_003"]
The offering key of the plan to assign
"pro-plan"
The billing interval for the subscription. Must be an interval available on the plan.
"monthly"
Optional entitlement or credit items to include with the subscription. Each item must have either a feature_key or credit_key, plus a quantity.
When true, subscriptions are created without generating invoices. Use this for customer migrations where payment has already been collected externally.