Introducing Surge: Revenue Boosting Predictive Hero Intelligence for Klaviyo Campaigns

Want the best of AI for email without uprooting your entire workflow? Backstroke Surge boosts email revenue by showing the best content to the right subscriber, all inside of Klaviyo. 

Every email team has had the same conversation.

"What if we sent this hero to buyers and this other one to browsers?" Then somebody runs the math on what it would take: build the segments, write the conditional content block, manage the merge tag logic, QA across audiences. The idea quietly dies. One hero ships to everyone. Again.

Which means the hero image, the most important pixel in an email, almost never gets personalized. Not because it shouldn't be. Because it's too much work.

Today, that changes.

Surge is predictive content intelligence—starting with heroes—for the Klaviyo campaigns you're already building. Upload 2–10 hero images and Backstroke scores each one against every audience segment on your list. A drag-and-drop content block appears in your Klaviyo account. You drop it into your email. Every subscriber sees the hero predicted to convert them. No segments to build. No conditional logic to write. No leaving Klaviyo.

The Category Split: Generative vs. Predictive

Most "AI for email" tools, including the AI features built into the major ESPs, are generative. They help marketers make more stuff, faster. A draft copy. A subject line. A hero image variant. Useful, obviously. But generating content is only half the job. The harder half is deciding which content goes to whom.

That's where Backstroke lives, and it's what makes Surge different from every other AI email tool on the market.

Surge is predictive—powered by more than 10 bespoke models. The models don’t just produce imagery. They score it against real audience segments before the email leaves Klaviyo. That's a fundamentally different category of tool, and it's why Surge can do something a generative-only tool can't: pick which hero is most likely to convert each subscriber based on what we know about how 100,000+ ecommerce brands perform in the wild.

The Money’s in the Models

Backstroke's predictive engine is trained on engagement data from more than 100,000 ecommerce brands, hundreds of millions of global consumers, and billions of clicks. That dataset is what turns hero selection from a guess into a prediction.

We've seen what that kind of predictive lift does when applied to hero images alone and the results are insane:

• MERSEA: 2.2X revenue; 83% higher conversion rate 

• Helix Sleep: 44% higher click through rate, 31% lift in conversion rate

• Perry Ellis: 21% increase in click rate, 46% lift in revenue per recipient

One Block. Zero Workflow Change.

A lot of teams are trying to adopt AI, but are grappling with the huge amount of work that’s required. We hear you. We can relate. Surge takes a different approach. It’s built so email teams can implement powerful AI models without changing how they work. Here’s how Surge works. 

1. Detect the campaign. Surge syncs your Klaviyo draft and scheduled campaigns automatically. You pick the one you're about to send.

2. Choose your heroes. Upload 2–10 variations. Mix Hero Lab outputs, your designer's work, stock imagery. The model scores them all the same way. If you can’t easily generate multiple options, check out our Hero Lab or talk to us about affordable Hero design services. 

3. Review predictions. See exactly which hero is going to which audience segment, what percentage of your list each one reaches, and which hero gets the default slot for new subscribers.

4. Create and drag. Click Create Block. A Universal Content block appears in your Klaviyo account, named after your campaign. Drag it into your email where the hero belongs. Preview. Send.

That's the whole thing. Your templates never leave Klaviyo. You don’t create new campaigns for every segment. You never write a merge tag. And because you pick the heroes, your brand team stays in control of what's shown. Only the scoring and matching are automated.

What's Next for Surge

Surge isn't a feature, it's a new category of Backstroke products. And it’s just the beginning.

Hero images are the first component we're predicting because the hero drives an outsized share of email clicks and revenue. But an email is a collection of components, and nearly every one of them can be predictively optimized. Today they ship static, because personalizing any of them demands the same manual segment-and-merge-tag tax that kills hero testing. Surge eliminates that tax, one component at a time.

Coming next under Surge:

• Predictive product ordering: grids reordered by audience, not by catalog feed

• Predictive headlines: copy matched to audience intent, not just brand voice

• Predictive CTAs: the right ask for the right subscriber at the right stage

It’s the same experience every time: pick your content, drag the block into Klaviyo, send, make money. The workflow stays simple, while the predictions (and performance) compounds.

Get Surging

Surge is live today for every Klaviyo-connected Backstroke account.

If you're already a Backstroke customer: log in, click Surge in the sidebar, and your next campaign is ready to be Surged. Start Surging →

If we've talked before: a lot has shipped since we last caught up. Let's reconnect and show you what's new.

If you're new here: see what predictive email looks like in practice. Book a demo and we'll walk you through it.

It’s time to juice up your email program with Surge.