Offer and book time-windowed delivery slots at checkout using a slot management API

Steps

1. Integrate a slot management platform (such as Urbantz) by obtaining API credentials and calling the carrier capacity endpoint at checkout to retrieve available delivery windows for the customer's area.
2. Pass the customer's delivery postal code or coordinates, the order's estimated weight and dimensions, and the desired delivery date range; the API returns a list of available slots with capacity, pricing, and earliest/latest delivery times.
3. Present the slot options in your checkout UI; when the customer selects a slot, POST a slot reservation to the API with the customer details, order reference, and selected window to hold capacity.
4. On order confirmation, convert the reservation to a confirmed booking by calling the booking confirmation endpoint with payment authorization; the API returns a booking reference.
5. Store the booking reference against the order in your OMS and pass it to the carrier or last-mile provider at label creation time so the slot is honored during routing.
6. Handle slot expiry: reservations typically expire if not confirmed within a defined window (e.g., 15 minutes); surface an error to the customer and prompt them to re-select if the reservation lapses.