Stronger puts SMS to the test – and beats email with 84% more revenue

Stronger has, for a long time, relied on the strong performance of email in their customer communication. But with an ambition to reach customers who were slipping through the cracks, Stronger’s Interim CRM Manager Malin Lundberg from Beyond Retail and Voyado set out to challenge the status quo and test if SMS could play a more strategic role in re-engaging these customers.

The question: if certain customers weren’t engaging with email, could a timely text message capture their attention—and ultimately drive more conversions and revenue?

The test

Two A/B tests were set up:

1. Defecting customers – targeting those showing signs of inactivity.
2. Email non-openers – targeting customers who had not opened a recent email within 24 hours.

Both groups received either an SMS, email, or no message (control group).

The SMS campaigns outperformed email across all key metrics. Revenue reached 95,214 SEK compared to 51,558 SEK for email, with conversions at 92 versus 60. Notably, SMS also drove a higher average order value of 1,035 SEK, compared to 869 SEK for email. On top of this, the ROAS from SMS was better than Stronger’s paid ads.

Looking into the differences between the two segments in the test we could see that the less active, “defecting”, customers showed a smaller uplift, while the real breakthrough came from the group who hadn’t opened an email — where SMS drove significantly higher conversions, revenue, and average order value than email.

The results showed that SMS has earned its place as a given tool to reach and activate customers. Unlike email, which can sit unopened, SMS is typically read instantly and prompts immediate action. And by using it for smaller, well-defined segments rather than broad send-outs, Stronger proved that SMS is best applied selectively as a complementary channel to ensure important messages cut through.

The future of SMS at Stronger

Following these results, Stronger sees great potential in weaving SMS more strategically into the customer journey — from time-sensitive promotions and back-in-stock alerts to VIP early access for loyal customers. Beyond individual campaigns, the channel opens up new opportunities to create urgency, drive exclusivity, and strengthen relationships with their most engaged segments.

With just two tests, SMS generated 84% more revenue than email and outperformed Stronger’s paid ads in ROAS. The results proved that, alongside email, SMS is not only a powerful complement but also a high-converting channel that delivers clear, measurable impact.