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.
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.
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.
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.
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.
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.
Known gotchas
Slot availability is dynamic — a slot shown as available at page load may be gone by checkout completion; always re-validate availability before finalizing the booking.
Carrier SLAs for slot adherence vary; avoid promising exact arrival times at checkout unless your carrier API guarantees them, as missed windows generate customer-service load.
If your platform does not use a dedicated slot API, approximate slot availability using carrier cut-off times and your own order processing lead time, making clear to customers that windows are estimates.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp