An online grocery service's pickers guessed at substitutions, and customers punished the guesses in reviews. We built a flow where every out-of-stock scan sends the customer two smart swaps on WhatsApp — their choice updates the order before the van leaves. Complaints fell 77%.
Typical results
84%
Customers reply before dispatch
4 min
Median swap decision
0 days
Refund wait, down from 4
Figures reflect typical results for this kind of automation.
The challenge
Roughly one order in three hit an out-of-stock item, and pickers had seconds to decide: skip it or substitute by gut feeling. Wrong guesses — whole milk for oat, the pricier brand — drove 31 complaints per 1,000 orders, refunds for skipped items took four days, and substitutions became the number-one reason customers churned.
Before and after
Substitution complaints per 1,000 orders
−77%Customers choosing their own swap
Days waiting for out-of-stock refunds
−100%The automation
We connected the picking app, the store and WhatsApp. When a picker scans an item as out of stock, the engine selects the two closest alternatives by category, brand, size and price, and the customer instantly receives a choice card: swap A, swap B or an immediate refund. One tap rewrites the order, invoice and picking list before the van is loaded; no reply within ten minutes applies the customer's saved preference.
How it works
- 01
Flag the gap
A picker scans an item as out of stock in the picking app — that scan is the trigger.
- 02
Suggest smart swaps
The engine picks the two closest alternatives by category, brand, size and price from live stock.
- 03
Ask the customer
A WhatsApp card offers swap A, swap B or an instant refund — one tap, no phone call.
- 04
Update everything
The choice rewrites the order, the invoice and the picker's list before the van is loaded.
- 05
Respect the fallback
No reply within 10 minutes applies the customer's saved preference and notes it on the receipt.
Starts from
- Picker out-of-stock scans
- Live stock & swap rules
Delivers
- WhatsApp choice card
- Auto-adjusted invoice
- Corrected order to dispatch
The impact
Substitution complaints dropped from 31 to 7 per 1,000 orders — down 77%. 84% of customers now pick their own swap before dispatch, with a median decision time of four minutes, and refunds for unavailable items land on the invoice immediately instead of four days later.
Questions about this automation
How are the two replacement options chosen?
When a picker marks an item out of stock, the engine searches live stock for the closest matches by category, brand, size and price. Rules set by the store, such as never swapping dairy for plant-based or capping the price difference, filter the options before they reach the customer.
What if the customer does not answer in time?
The WhatsApp card stays open for ten minutes. With no reply, the automation applies the customer's saved preference, such as always refund or allow a similar brand, and notes the choice on the receipt. Pickers never have to wait on the customer to keep the order moving.
Which systems need to be connected?
The picking app, the online store or order system, and WhatsApp Business. The customer's choice updates the order, the invoice and the picker's list at the same moment, so refunds for skipped items appear on the invoice right away. Simple automations like this are usually live within days.