Key Takeaways
- A multi-line order can leave the building in three boxes. One “your order shipped” SMS is a lie after the first carton.
- Backorder “we have a date” is operational. “Buy a similar SKU” is promo with STOP.
- Free is 1 device, 300 SMS lifetime, and 300 contacts. Developer is 25,000 SMS per year. Platform price is devices plus send volume.
- Checkout OTP stays off the fulfillment-notify SIM.
- Idempotency is line-id plus carton event — not the parent order id.
Summary
Scenario 301 is ecommerce webhooks for split shipments and backorders — not checkout HMAC, not COD, not dunning, not RMA, not drop allocation. One checkout, several cartons, missing lines. Customers need a text per carton that actually left, plus an honest date on what did not. Service pricing is devices plus SMS send volume. You bring the phone and operator credit. Free is 1 device, 300 SMS lifetime, and 300 contacts.
Starter allows 2 devices: fulfillment notify vs OTP. Uncapped platform volume is not unlimited carrier SMS. Confirm events in Developer Center.
line A scan · line B hold · backorder date
parent order-id is not a send key
Split shipment is not one “shipped” lie
Carton 1 scan: those SKUs only. Carton 2 later: a second SMS. Do not reuse “your order is on the way” after the first box. Label print is still silent — first-mile scan is the radio event.
If line B is backordered and you key on order-id, the second carton never texts — or the first SMS repeats. Key line-id plus carton-id. Partial truth is worse than silence.
Backorder webhook matrix
| Event | SMS? | Failure |
|---|---|---|
| Line first-mile scan | Yes — those SKUs | “Whole order shipped” |
| Line backordered | Yes — date or “TBD owned” | Similar-SKU coupon in the same text |
| Pick complete | No | Three texts before a truck exists |
| Cancel remaining | Yes — refund path, no upsell | Win-back on the ops SIM |
Line-id, not order-id
Persist line-id + carton event. Signed webhooks. Live JSON in Developer Center. MCP wraps REST only. DLR is radio, not “box on the porch.”
Backorder promises
If you do not have a date, say so. Do not invent ETA from a vendor rumor. Google Ads SMS/MMS policy for substitute-SKU promo.
Devices, volume, and airtime
Split orders multiply sends. Budget it. We meter devices and platform volume. Free (1/300/300) is a staging store.
Warehouse-week operations
Pairing, charge, OTP isolated, staff canary on a two-line order. Setup, Downloads, pricing.
Decision guide
Ship when carton SMS cannot claim the whole order. Delay if marketing owns fulfillment webhooks. Not a CodeCanyon “unlimited SMS” pack.
Split-ship checklist
- Key = line-id + carton event.
- First-mile scan, not label print.
- Backorder copy has no coupon.
- OTP isolated.
- Developer Center fields confirmed.
Next steps
Scenario 1 checkout, scenario 181 RMA, scenario 241 drops.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- SMS webhook integrationInbound and status events
- transactional SMS for orders and alertsEvent-driven messages
- SMS API documentationLive endpoint reference
- PHP REST send samplesPHP code examples
