Guides

PromisePro - Delivery Estimation

PromisePro is a service that answers one question for any item, anywhere: can we get it to this shopper fast — and exactly when will it arrive? Give it an item, a quantity, and a destination ZIP, and it returns the order-by cutoff time and the resulting delivery date from the fastest fulfillment center that can actually ship it.

It's built to power delivery promises on storefronts — the "Order within 4h 12m → arrives Tuesday, Jun 24" badge that turns a vague "ships soon" into a concrete, trustworthy commitment at the moment of purchase.

What it does

Behind a single request, PromisePro:

  1. Finds which fulfillment centers (FCs) currently have the item in stock (at least the requested quantity).
  2. Looks up shipping routes from those FCs to the shopper's ZIP.
  3. Picks the fastest viable option, and if today's order cutoff has already passed, rolls forward to the next day that can still deliver — so the cutoff it returns is always in the future.

The request and response, at a glance:

GET /v1/delivery-estimate?item_id=ABC123&qty=1&destination_zip=75087
{
  "cutoff_time": "2026-06-24T00:00:00Z",
  "estimated_delivery_date": "2026-06-26",
  "transit_days": 2
}

If the item can't be promised — out of stock, no route to that ZIP, or unknown item — it returns a clear status instead of a guess. It never invents a delivery date.

Two ways to use it

1. The drop-in widget (recommended). A small, self-contained script renders the delivery-promise badge on a product page, calls the API for you, and shows the live countdown — only when the delivery is genuinely fast. It's fail-closed: if anything is off, it shows nothing rather than a weak or misleading promise.

  • Developer Guide — embed the widget on any storefront (Shopify, BigCommerce, custom, headless): attributes, theming, environments, troubleshooting.
  • Shopify Setup (for merchants) — a non-technical, ~15-minute walkthrough to turn the badge on in a Shopify store.

2. The API directly. Call GET /v1/delivery-estimate from your own front end, app, or back-office tooling.

  • API Reference — parameters, response shape, and status codes.

Good to know

  • It never overpromises. A delivery date is returned only when an FC both stocks the item and has a fast-enough route to the ZIP; otherwise the caller gets a clear "no estimate" status.
  • US-only today. Destination is a 5-digit US ZIP.
  • Public and rate-limited. The widget endpoint is open (no key) and capped at 100 requests/second, with CORS enabled for in-browser use.
  • Always current. Inventory and routes refresh continuously from the systems of record, so estimates reflect what's actually sellable and shippable now.

Where to start