A delivery date answers "which day." A time slot answers "when that day" — and for a lot of merchants, that's the difference between an efficient delivery route and a wasted one. This guide shows how to offer delivery time windows on Shopify, cap each one, and enforce the choice at checkout — with no code.
Why time slots, not just dates
Same-day and local-delivery merchants live and die by routing. If everyone picks "Saturday," you still don't know when to send the van. Time windows — 10:00–12:00, 14:00–16:00, 18:00–20:00 — let customers self-select into the capacity you actually have, and they match the fixed windows Japanese carriers already use.
Delivery slot, delivery window, date picker — which is which?
These get used interchangeably and they aren't the same thing.
| Term | What it is |
|---|---|
| Delivery date picker | The calendar the customer chooses a date from |
| Delivery slot | A bookable time band on a date — 14:00-16:00 — with its own capacity |
| Delivery window | The range you show as an estimate — "arrives 10-11 July" |
| Shipping date picker | Loose wording for the same calendar, though shipping date properly means the day it leaves you |
The distinction that matters operationally: a window is a prediction you make, a slot is a commitment the customer books. Slots carry capacity, so ten bookings in a 14:00-16:00 slot is ten deliveries you have promised for that band. Windows carry no capacity at all.
How it works in OrderRules
On the Advanced plan, time slots attach to any availability rule:
- Define your windows. Add the slots you offer; they appear under the chosen date on the storefront picker.
- Cap each window. Give a slot its own capacity so it can sell out independently of the date. See delivery capacity limits.
- Live sell-out. Full slots grey out automatically — customers only see what you can fulfill.
- Checkout enforcement. The OrderRules Shopify Function blocks a sold-out or invalid slot, even on Shop Pay and express checkouts.
Slots that map to your carrier
Your windows are carrier-agnostic. At export, OrderRules maps each slot to the carrier's native slot code — so 14:00–16:00 becomes the right code for Yamato, Sagawa, or Japan Post automatically. See Carrier CSV export.
Set it up
- Open Delivery → Availability rules and edit a rule.
- Add your time slots, and a per-slot capacity if you want windows to sell out.
- Save. Slots render under each date; checkout enforces them.
Full detail: Time slots. For the complete flow, start with How to add a delivery date picker to Shopify. Offering collection instead of delivery? Time-window capacity works the same for in-store & local pickup.
See the Delivery Dates feature or start a free 14-day trial.