We don't promise an amount; that depends on your range. What cross-selling from purchase history can do is shown by a McKinsey case study: an online retailer that introduced it, by email and on-site, grew its yearly sales by about 20% and its profit by about 30%. That is one case, not an average. You see your own numbers on the Free plan: 100 recommendations per cycle, every attributed order in your dashboard, and never a bill. The case study →

Nothing. You get the full product and we charge no fee. We announce the end of the launch phase at least 14 days in advance; after that you choose: Free (100 recommendations per cycle sent free, then sending pauses until the next cycle — you can never be charged) or Fair (continuous sending, 6% of the extra revenue extra carts demonstrably delivers). Uninstall anytime — there is no subscription.

No. On the Fair plan, we charge 6% only on the gross merchandise value of attributed orders. Example: €100,000 from other orders and €10,000 from attributed orders result in a €600 fee. That is about 0.55% of the €110,000 total. This is an arithmetic example, not a revenue forecast.

A fair question. Honestly, today we can't yet prove whether an order would have come without us; a test for that, and an automatic credit when the recommendations demonstrably deliver too little, are planned after the launch phase. What protects you today: we only charge when the link between our recommendation and the products bought is clearly visible. Direct visits, other ads and your own newsletters are never charged. On the Free plan, 100 recommendations per cycle show you real results and would-be charges before you switch to Fair.

Honest answer: below roughly 300 orders in 60 days, the patterns of what sells together are too thin. Then we don't send, and we tell you so openly in the dashboard instead of shipping weak recommendations — activating automatically once the signal is strong enough. The app fits best for stores from about €10,000 in monthly revenue.

Keep it. The difference isn't the sending, it's the choosing: your flow sends what you or your agency put into it. extra carts works out, for every single order, which product is missing from what is frequently bought together in your store, checks stock, similarity under UWG §7(3) and consent — and sends only then. No fitting product, no email. Our sends are hard-capped: at most one per customer every 14 days. We don't coordinate your other emails; we only count ours. We keep improving the subject lines; once there are enough sends, we learn from anonymous counters across all connected stores, not just your own sends. You pay nothing for sending.

The timing. Cross-selling in your store works while your customer is still shopping. extra carts starts after payment: right on the page after checkout and by email once your customer has left the store. You switch each of these places on or off individually, so extra carts runs alongside what you already have.

They're a good start. extra carts picks, for every single order, the product from what is frequently bought together in your store, checks stock, similarity under UWG §7(3) and consent before every send, compares subject-line variants anonymously across all connected stores, and hands you a receipt for every extra order. You pay only when an extra order actually results — no subscription, no license. And if you'd rather optimize yourself: the Free plan shows you, at no cost, what's in your own orders.

You see it before anyone else: every template is shown to you up front, and you approve the first batch yourself — nothing sends behind your back. What you can't do is rewrite the copy, and that's on purpose: no flow builder, no blank page, no weekend lost to email design. The template is pre-tested, conservative and compliance-checked, your shop name is the sender, and it only ever shows your products — so it stays on-brand and within UWG §7 with zero work from you. You keep control where it counts: switch tone (Sie/Du), exclude any product or category, mark pairs as 'never recommend together', tighten the frequency cap, or pause sending — anytime.

It only ever recommends your own products — and only ones that are in stock and genuinely similar to what the customer just bought; the similarity check runs before every send. You approve the first batch before anything goes out, and you can exclude any product or whole category, or mark pairs as 'never recommend together', anytime. During the launch phase we also review every batch by hand to catch anything off.

Because it's one at most — and often none. It sends at most one email per order with exactly one product, and only when your order data clearly points to one. On top of that, fixed limits: at most one recommendation per customer every 14 days, never more than four in 90 days, never the same product twice; a STOP reply unsubscribes. And because we only earn on extra revenue, every needless email is a cost without return for us. We only ever send to existing customers with valid marketing consent in Shopify.

No. Every shop's data stays isolated — your customers, your orders and your co-purchase patterns — what sells together in your store — are used only to recommend your products to your customers, and are never exposed to another merchant. One thing we disclose before it does anything: every template ships with two to three subject-line variants that rotate randomly from the very first send. Which variant lands better is counted as anonymous statistics across all connected stores — evaluated only once ten merchants and a thousand sends are reached, never using customer data, never traceable to your shop. That's how the shared subject-line patterns improve without your data ever leaving your shop.

Your data stays isolated to your shop, encrypted at rest, and hosted in the EU. No other merchant sees it; inside extra carts access is least-privilege, and during the launch phase a reviewer only looks at a batch to catch a bad send before it goes out. We're your data processor under a DPA signed at install — exactly two sub-processors are listed: Brevo (email delivery) and Hetzner (hosting, EU locations only); error monitoring runs on our own infrastructure. You get 30 days' notice of any change. Uninstall and we delete your customers' personal data within 48 hours. We earn a fixed share of the extra revenue — not your data.

Recommendations go only to existing customers and only for similar products — the UWG §7(3) similarity check runs before every single send, as does the check against your Shopify consent flags. Unsubscribing happens right from the email: a STOP reply is enough and takes effect immediately. If the legal basis for a recipient is unclear, nothing is sent. More on the emails →

One rate, no table: 6% of the gross merchandise value (incl. taxes, excl. shipping) of extra orders demonstrably generated by our recommendations — last click, 7-day window. That applies to the Fair plan; on the Free plan, 100 recommendations per cycle are sent free, then sending pauses — there you can never be charged. Billing happens at the end of each Shopify billing cycle (30 days), as one line on your bill — orders cancelled or fully refunded by then are never billed.

No — and that's not a marketing promise; it's in the fee terms you approve at install: the rate can only ever decrease, never increase. The 6% is the same for everyone, there are no hidden tiers. And because the fee is a fixed share of the extra revenue, your bill can only grow if your extra revenue grows.

Every attributed order has an evidence record: which email, which click, which timestamp, which order. Never billed: cancelled, refunded and test orders — and anything that can't be attributed cleanly. When in doubt: no charge. Everything exports as CSV.

No. Besides the email after the purchase, extra carts shows a recommendation right after checkout that your customers can add to the same order with one click. Shopify shows that page only when the customer paid by credit card. In time, extra carts aims to help inside the store and at other moments when customers may buy again. A recommendation on the thank-you page is planned next; the cart, product page and winning inactive customers back are other possible steps. There are no dates for these features yet. You see and approve new features and terms in the app beforehand.

We do — from our own authenticated sending domain (email.extracarts.net) with SPF, DKIM and DMARC; your shop gets its own sender address there (yourshop@email.extracarts.net). Your own domain and sender reputation are never touched. Your shop name appears as the sender, replies are forwarded to your support address — and anyone who wants no more recommendations simply replies STOP: it takes effect immediately and permanently.

Four — and all of them read-only: orders from the last 60 days, customers (consent state and email address only), products and product listings for the legally required similarity check. extra carts requests no write permissions. We never change your customers' consent — and a STOP reply goes onto our own suppression list without touching your Shopify data.