A WhatsApp post-purchase upsell (or cross-sell) is a product offer sent to a customer right after they confirm their order on WhatsApp, which they can add to that same order without checking out again. Cartsaver is a Shopify upsell app that does this on WhatsApp: it adds the chosen item to the customer's existing Shopify order, so it ships in the same parcel.
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In Cartsaver, it happens in the same WhatsApp thread as the order confirmation: the customer taps a product and picks the size or color in the chat, without going back to your store. Cartsaver is a Built for Shopify app by Xtnd that confirms cash on delivery orders on WhatsApp or SMS before you ship, then uses the same WhatsApp conversation for order updates, abandoned cart recovery, one-tap cross-sells, reviews and campaigns, through the official WhatsApp Business API. This page explains how Cartsaver's Cross-selling works, which products to offer, how the discount and the order edit behave, and how to read the results. It is written for Shopify merchants who sell with cash on delivery, in Egypt, the Gulf, Pakistan, India and beyond.
Which Shopify app sends a WhatsApp cross-sell after a COD order is confirmed?
Cartsaver does. When a customer taps Confirm on the one-tap WhatsApp confirmation for a cash on delivery order, Cartsaver waits the time you choose (15 minutes by default), then sends one product or a carousel of up to 10 in the same chat. The customer picks a size and color there, and Cartsaver adds it to the existing Shopify order.
Why is the moment after confirmation the best time to cross-sell?
Right after a COD customer taps Confirm, they have just said yes to buying, the WhatsApp chat with your store is open, and the order has not shipped. An add-on offered then joins the same parcel and the same cash payment, so the customer pays no second shipping fee.
Most Shopify post-purchase upsell apps work on the thank-you page, which assumes the customer paid by card and is still looking at your store. A COD customer often closes that page within seconds. What they do open is WhatsApp, because that is where your order confirmation arrives.
When they tap Confirm on your one-tap WhatsApp order confirmation, three things are true at once: they have just said yes to buying, the conversation with your store is open, and the order has not shipped yet. An add-on offered then can join the same parcel and the same cash payment on delivery. For the customer that means one delivery and no second shipping fee. For you it means a bigger order with no extra packing run and no extra courier trip.
How does the WhatsApp cross-sell work?
After the customer taps Confirm on the WhatsApp order confirmation, Cartsaver waits the time you choose (15 minutes by default), then sends one product or a carousel of up to 10 in the same chat. The customer picks a variant inside WhatsApp, and Cartsaver adds it to their existing Shopify order.
Watch the cross-sell walkthrough (Arabic). Step by step:
- The customer confirms. They tap Confirm on the WhatsApp Order Verification message for their COD order.
- Cartsaver waits the time you choose. The cross-sell message goes out 15 minutes after confirmation by default. You can set any wait from 5 minutes to 6 hours, so it does not land on top of the confirmation.
- The offer arrives in the same chat. One product, or a carousel of up to 10 products, each with its image and price. If you set a discount, the reduced price is shown.
- The customer picks size and color in WhatsApp. Tapping a product opens a selection screen inside WhatsApp that only lists variants that are available to buy.
- Cartsaver edits the Shopify order. The chosen variant is added to the customer's existing order as a new line item, with any discount applied. No new order is created.
- The customer gets a confirmation. A WhatsApp message confirms the item was added.
Before editing, Cartsaver checks the order again. If it has been cancelled, fulfilled or closed in the meantime, the item is not added, because Shopify no longer allows that order to change for shipping.
What the video covers
- 0:00 Intro: after the customer confirms their order, Cartsaver sends a WhatsApp offer they can add to that same order.
- 0:17 Setup and choosing the products: switch Cross-Sell on and pick the product source: Shopify recommendations, a Shopify collection, or products you hand-pick.
- 1:00 Discount and performance: add an optional percentage or fixed-amount discount, then follow sales, conversion rate and revenue for the last 30 days.
- 1:25 What the customer sees on WhatsApp: the suggested products arrive in the chat; the customer picks a size and color, and the item is added to their existing Shopify order.
Choosing the products: three sources
In the Cross-Sell settings you pick where the offered products come from. Each source suits a different catalog.
| Source | What the customer sees | Best for | Watch out for |
| Hand-picked products | The same list you choose, after every confirmed order | A small set of proven add-ons: accessories, refills, gift wrap | A customer may be offered something already in their order |
| A Shopify collection | Up to 10 products from the collection, in the collection's sort order | Stores that already keep an "add-ons" or "under 200" collection | Sort the collection so your best add-ons come first |
| Shopify recommendations | Related products for the items in this order (complementary recommendations are coming soon) | Larger catalogs where one list does not fit every order | Quality depends on Shopify's recommendations for your products |
With Shopify recommendations, Cartsaver offers Related products (items similar to what was bought). Complementary recommendations (items that go with the purchase) appear in the settings as coming soon. Products already in the order are left out automatically. In every source, only active products with an image are shown, up to 10 per message.
In Cartsaver's Cross-Sell settings you choose hand-picked products, a Shopify collection or Shopify recommendations as the source.
What makes a good add-on
A cross-sell is a small, easy yes at the end of a decision the customer already made. It is not a second sales pitch. In practice:
- Keep the price low next to the order. A phone case after a phone, socks after shoes, a travel size after a full bottle.
- Offer what goes with the order, not more of the same. After a pair of jeans, hand-pick a belt or a basic t-shirt, or use an add-ons collection, rather than offering more jeans.
- Do not offer your hero product again. Asking for a second big decision stalls the moment.
- Pick items that need no explaining. If the customer has to research it, it does not belong in a chat offer.
- Check stock and images. A product without an image is skipped, and sold-out variants are not offered.
Can I discount the cross-sold item?
Yes. You can attach an optional percentage or fixed-amount discount to cross-sold items. Cartsaver applies it directly to the added line item, so you do not need a promo code, and it only reduces the extra item, not the order the customer already confirmed.
You can attach an optional discount to cross-sold items, as a percentage or a fixed amount. The discount is applied directly to the added line item, so you do not need to create a promo code. It is visible on the Shopify order and in the order's edit history, which keeps your accounting and any courier invoice clear about what the customer will pay on delivery.
A modest discount works well here because it is framed as a reward for confirming, and it only applies to the extra item, not to the order the customer already committed to.
Tracking cross-sell results
The Cross-Sell card in Cartsaver shows the last 30 days:
- Messages sent: how many confirmed orders received an offer.
- Completed sales: how many customers added an item.
- Conversion rate: completed sales as a share of messages sent.
- Revenue: the value of the added items.
- Top products: which add-ons customers choose most.
The Cross-Sell Orders page lists each addition with its order, product, variant, quantity, unit price, total and date, and cross-sell revenue is also counted in your dashboard's revenue figure. Use top products to prune your list: if one item gets most of the sales, put it first or build the collection around it.
Plans and limits
Cross-selling is on every plan. The limit counts completed cross-sells per 30-day billing cycle, not offers sent: Advanced ($9.99/month) and Unlimited ($29.99/month) include 30, the Free plan includes 10, and Scale ($79.99/month), Ultra ($159.99/month) and Elite ($349.99/month) are unlimited. Cartsaver warns you near the limit and pauses offers once it is reached. See the full pricing table.
Setting it up
- Make sure your store uses WhatsApp Order Verification with the one-tap Confirm button. The cross-sell follows a tap on that Confirm button, Fast Checkout orders included, so it is not sent after a typed OTP code.
- Open Cross-Sell in Cartsaver, choose your product source and select the products, collection or recommendation type.
- Optional: add a discount for the cross-sold item, and set how long to wait after confirmation before the offer is sent.
- Switch Cross-Sell on, then place a test COD order with your own WhatsApp number and tap Confirm. The offer should arrive after the wait you set (15 minutes by default).
To choose between hand-picked products, a collection and Shopify recommendations, see the cross-sell product source settings in the Cartsaver docs.
Common mistakes
- Fulfilling orders too fast. If you mark orders fulfilled straight after confirmation, the customer's add-on can no longer join the order. Leave the cross-sell window open before you fulfill.
- Offering expensive items. A cross-sell that costs as much as the order invites a "no" and can make the customer rethink the whole purchase.
- An unsorted collection. With the collection source, the first 10 products in the collection's order are offered. Put the best ones on top.
- Never looking at top products. The results card tells you which add-ons work. Replace the ones that never sell.
A worked example
A Lahore skincare store sells a face serum on COD. Its cross-sell source is a hand-picked list: a travel-size cleanser, a lip balm and a cotton pad pack, all priced well below the serum, with 10% off. Sara orders the serum at 7 pm and taps Confirm on the WhatsApp verification message a few minutes later. About 15 minutes after that, a carousel of the three products arrives in the same chat. She taps the lip balm, chooses the "rose" shade from the shades still in stock, and confirms. Cartsaver adds it to her existing order at the discounted price, and she receives a WhatsApp message that it has been added. The store packs one parcel, the courier collects one cash payment, and the sale appears on the Cross-Sell Orders page.
Cross-selling is one of several things Cartsaver does in the same WhatsApp conversation. After delivery, the WhatsApp review request with Buy It Again invites a repeat order of the same products. See every Cross-selling feature on the homepage.
Frequently asked questions
Does the cross-sell create a second Shopify order?
No. Cartsaver edits the customer's existing order and adds the item as a new line item, so it ships in the same parcel and is paid in the same cash on delivery payment.
Can customers choose size and color in WhatsApp?
Yes. Tapping a product opens a selection screen inside WhatsApp that lists only the variants available to buy. The customer never leaves the chat.
When is the cross-sell message sent?
After the customer taps Confirm on the one-tap WhatsApp order confirmation, once the wait you choose has passed: 15 minutes by default, adjustable from 5 minutes to 6 hours. It is not sent if, by then, the order has been cancelled, Cross-Sell has been turned off, or your cross-sell limit or credits have run out.
Is cross-selling sent by SMS too?
No. Cross-sell offers are sent on WhatsApp only, because they rely on product images and an in-chat selection screen.
How many cross-sells are included in my plan?
Advanced and Unlimited include 30 completed cross-sells per billing cycle, the Free plan includes 10, and Scale, Ultra and Elite are unlimited. Offers that the customer does not accept do not count.
Does Shopify's post-purchase upsell page work for cash on delivery orders?
No. Shopify does not show its post-purchase page when the order was paid with anything other than a credit card, so COD buyers never see it. Cartsaver does not use that page. It sends the offer on WhatsApp after the customer confirms, and adds the accepted product to the existing Shopify order. Install Cartsaver from the Shopify App Store and start on the Free plan, no credit card needed.