Bone Brox has become the best-known German bone broth brand within just a few years. The promise behind it is clear: traditional broths and bone broths in organic quality, cooked by hand for 24 hours, with no shortcuts and no additives. Recommended by Olympians and nutrition experts, loved by a loyal community. Founders Konrad Knops and Jin-Woo Bae have turned a niche product into a true love brand.
Challenge
Bone broth is a consumable product. Once customers are convinced, they usually buy regularly. But weeks or months often pass between two purchases. During that time, customers simply forget, and no habit forms. Email cannot reliably reach every customer for activation. If someone does not open the newsletter, they do not receive the reminder and miss product news. That was the starting point at the beginning of 2026. Bone Brox wanted to reactivate inactive customers, including BFCM buyers who had never ordered again after Black Friday, as well as repeat buyers who had not purchased for a long time and had recently stopped opening emails. The channel through which these customers could still be reached reliably was the mailbox.
Solution and campaign
Bone Brox chose a segmented postcard campaign for the turn of the year. Using the native PostPal integration in Klaviyo, several winback and reactivation segments were targeted directly. No new system, no manual export work. The segment logic already used for email flows automatically triggered postcard delivery. In total, cards went to seven different segments, including winback recipients who had completed the email flow without purchasing, repeat buyers whose last purchase was 60 to 1,080 days ago, BFCM one-time buyers and very long inactive customers. All recipients had one thing in common: email no longer reached them reliably.
The design
The front uses strong imagery: an action-packed family scene with a father and children, full of energy and joy. It is paired with the clear headline “For a powerful 2026!” and a striking pink badge saying “Now 25% off”. No product photo. Emotional brand world instead of product catalogue. The back is focused consistently on conversion. Each card includes a personal greeting with the recipient’s first name, an individual voucher code and an individual QR code that leads directly to the shop. Both founders signed personally: “Powerful greetings from Potsdam.” The card also promotes the new bone broth concentrate and names the portion size, 46 portions, as a concrete purchase argument. Every card is assigned clearly to one recipient and can be tracked end to end.
Results
The campaign delivered very strong results*: The following numbers are based on the voucher view, meaning only conversions where the individual campaign code was redeemed were counted. This is the most conservative measurement view.
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€41,033 net revenue at 1,359% ROAS
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8.8% conversion rate across all segments
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Strongest segment: winback recipients whose last purchase was 61 to 1,080 days ago and who had made more than one purchase: 20% conversion rate, 3,455% ROAS
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Repeat buyers respond more strongly: the repeat-buyer segments consistently achieved significantly higher conversion rates than one-time buyers, with up to a 3.5x ROAS advantage
“We contacted customers who had not opened email for a long time. The postcard reached them where email had stopped working. Segmentation ran directly from Klaviyo, without additional effort. Achieving a ROAS of more than 1,300% clearly exceeded our expectations.” Konrad Knops, Founder & Managing Director, Bone Brox Measurement method: voucher view. Tracking window: 60 days.