How KSD Increased Purchases from a Birthday Trigger by 62% in Email and 66% in Viber

About the Project

Klub Simeinoho Dozvillia (Family Leisure Club) is a large publisher, founded in 2000. Over more than 25 years, the company has evolved into a vertically integrated, full-cycle business: from publishing its own books and licensing international bestsellers to a multichannel distribution system (online sales, its own retail, and wholesale).

KSD's birthday communications were already running in email and Viber and included personal gifts for customers. However, the team saw room for growth: they needed to make the messages more noticeable, understand which format drove purchases better, and improve the performance of both email and Viber.

The team focused specifically on the "One from Many" block. Manually analyzing results, identifying winners, and implementing changes took too much time, so KSD wanted to move from one-off hypothesis checks to a systematic approach that would help find the best-performing content faster and scale it.

Objective

The main goal of optimizing the "Happy Birthday" trigger was to improve engagement metrics. In particular, the team needed to find the most effective message variants that would encourage customers to buy during the holiday period.

Solution

Until June 2025, the brand used separate greeting messages in email and Viber. To find the best-performing variants across both channels, the team chose Yespo's continuous A/B testing block, "One from Many."

The main reason was speed: there is no need to wait for a test to finish and implement the winner manually. The system tracks in real time which variant performs better and gradually starts sending it more often, with no additional effort from the marketer.

"One from Many" also helps prevent a common drawback of traditional A/B testing: lost conversions while underperforming variants remain active. In a standard test, you have to wait for it to end even when one of the variants performs worse from the start, which hurts results. The "One from Many" block optimizes campaigns on the fly by excluding underperforming variants right away.

Sending Conditions and Workflow Logic

To avoid an excessive number of notifications and increase loyalty, strict rules were set up: messages are sent only at a time that is convenient for the customer (communication starts at 11:00).

Implementation stages:

1. Updating email templates: emails were prepared in a design that matched the new look of the website.
2. Preparing variants for testing: 3 email variants and 3 Viber message variants.
3. Implementing the "One from Many" block in the trigger workflow: the system automatically distributed traffic between the variants and, over time, focused on the one with the highest conversion.

Testing in the Email Channel

During the redesign of the KSD website, the team updated the email design in parallel so that the communication style stayed consistent. The templates were also adapted to display correctly on both mobile devices and desktop.

Preparing Variants for Testing

Starting in June 2025, the brand began sending the greeting email in the new design. In July, two more variants were added to the existing one, and testing of all three was launched.

To test with the "One from Many" block, each email variant was assigned the same labels ("trigger" and "bday"), and they were then added to the corresponding block of the workflow. This allowed the system to automatically distribute recipients among the three email variants.

Initially, all variants were sent in equal volumes, but after just one month, one of the variants was automatically identified as the best, and the system began prioritizing that email and sending it in larger volumes, with no additional effort from the marketer.

The test produced the following metrics:

• As a result, purchases from the email channel showed positive momentum: from July 2025 to January 2026, they grew by 62.3%. The upward trend continued throughout the period.
• Conversion rate grew by 88.1% compared with July.
• Revenue per email grew by 70.7%.

Testing in the Viber Channel

Testing in Viber took place in two stages.

Karina Bohush, Email Marketing Specialist at Yespo

 

As a result, purchases from the email channel showed positive momentum: from July 2025 to January 2026, they grew by 62.3%. The upward trend continued throughout the period. Conversion rate grew by 88.1% compared with July. Revenue per email grew by 70.7%.

Stage 1: Finding the Best Text

We prepared 3 different texts and launched testing on 22.06.2025. At first, the system sent them evenly, but by the end of July 2025, it had identified the most effective variant and started sending that one more often.

Variant 3 (leader): it had the highest click-through rate (CTR 18.5%). The open rate (OR) was virtually the same in all three variants, so the deciding advantage of Variant 3 was its CTR – it outperformed Variant 1 and Variant 2 by 31.2%.

Purchases over this period grew by 61.5%, and notification conversion rate increased by 33.8%.

Revenue per notification in July was 84.6% higher than in June.

After that, only the third variant was sent until October 2025, and starting on October 14, 2 more alternative variants were prepared. This time, the team decided to test different visual approaches. 

Karina Bohush, Email Marketing Specialist at Yespo

 

We decided to test visuals separately to see whether the image affects the reader's reaction. At first, we used a banner with only an intriguing line of text, but then we decided to check new hypotheses. It was important for us to understand whether customers would respond better if we showed the gift itself visually, or if we added a block with additional product recommendations to it.

Stage 2: Finding the Best Image

1. Variant 1 – the winning message from the previous testing stage.
2. Variant 2 – a message featuring an image of the gift. 
3. Variant 3 – an interactive message: the first image showed the gift, and the following ones showed book recommendations, including bestsellers and new releases.

Variant 2 (winner): The open rate (OR) was virtually the same across all three variants, so CTR was the deciding factor. Variant 3 was turned off because of the lowest click-through rate, 37.2% lower than Variant 2. Variants 1 and 2 were kept active because the difference between them is minimal, only 1.0% in favor of Variant 2.

Purchases over the test period grew by 84.8%, notification conversion rate by 81.8%, and revenue per notification by 115.7%.

It is important to note that the increase in purchases was not tied to an increase in sending volume. The team additionally checked the number of messages sent across both channels in the first and last months of testing: it stayed at practically the same level. So the growth in purchases can be viewed specifically as the result of content optimization and the automatic prioritization of the best-performing variant.

Conclusions

The KSD case shows that automatic content testing can become a continuous process rather than a one-off experiment. With the "One from Many" block in the "Happy Birthday" trigger, the team not only tested several hypotheses but also set up a mechanism that automatically amplifies the best-performing variants.

Key achievements of the "Happy Birthday" trigger for the period June – January:

• Email purchases grew by 62.29%, and conversion grew by 88.1% compared with July.
• Viber purchases grew by 66.14%, and notification conversion rate increased by 49.3%.
• Automating content selection enabled the brand to grow purchases without manually managing each test.

Next Stage of Scaling

After successfully testing the "Happy Birthday" trigger, the brand began using the "One from Many" block in other trigger workflows as well. This made it possible to automate testing and scale the best-performing content variants.

The block is now used in 13 trigger workflows. The strongest growth in metrics is seen in the following triggers:

• "New Arrivals" – the number of purchases grew 2.4 times (from August 2025 to January 2026).
• "Wishlist Item Back in Stock" – the number of purchases grew 2.2 times over the same period.

At the same time, the team regularly improves its test variants. In particular, it updates additional blocks, banners, email subject lines, and button placement.

Tetiana Pozdniakova, KSD Marketing Specialist

 

When we started working with Yespo, we set several goals:

• determine the overall performance of each communication channel and understand which channels generate the highest conversion rates;
• get the ability to filter the customer database conveniently, simplifying the work of our own specialists;
• implement push notifications for customers in our app;
• build a convenient and cost-effective system of triggers, so as to both keep customers informed and prevent spam.

Over the year, we made significant improvements to our communication. We can track customer reactions better, and we can quickly adjust to various changes. The tools available in Yespo for creating emails made our mailings more attractive and interesting for customers and supplemented the standard messaging with gamification and various interactive elements.

Beyond the improved metrics in our reports, we're also pleased with the brand image we've created. Thank you to the team for the work, quick responses, and support.

Plans for the Future

The brand plans to keep using the "One from Many" block for automatic testing and scaling of the best-performing variants. In April 2026, KSD also added new communication channels, mobile push and app inbox, to its trigger workflows, including the birthday trigger. In the future, the brand plans to extend automatic testing to these channels as well.

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