The default setting for Splitit plans is multiple monthly installments. It is also common for shoppers to pay the first installment at checkout. There are however, other options for installment plans, most of which Splitit support can set for you.
Your merchant account can be set by Splitit support to offer installment plans on a biweekly basis instead of a monthly basis. If you are using a form, your shoppers will see biweekly calculations when they go to sign up for a plan, instead of monthly calculations.
You can verify that your account is set to biweekly by calling the CheckEligibility endpoint and viewing the value under InstallmentFrequency.
You can delay the first installment payment for your shoppers by a specific number of days. Subsequent payments are calculated related to this first delayed payment (e.g., thirty days out from this payment, sixty days out from this payment, etc.). Splitit support will need to set this for you.
Pay At Delivery
Using API v3, you can have your shopper pay when the product is shipped by creating an installment plan with a single installment and setting AutoCapture to false. Splitit will perform an authorization for the full amount of the plan. After your products have been delivered to your shopper, you will need to call one of the UpdatePlan endpoints with ShippingStatus set to Delivered and Capture set to true.