Most founders chase viral moments. These three engineers figured out how to manufacture them on repeat. In today's recap of our podcast interview, our host Joseph sat down with Peter from Stronger, a gamified workout tracker that's pulling in $600K in annual recurring revenue with 1.2 million users. The team discovered something most marketers would kill for: a content format so reliable they've posted variations of it...300 times...and it still works.
As always, if you haven't seen the interview yet, definitely check that out right here. For now, on to the recap:
The fade-in format that shouldn't work, but does
Stronger discovered what they call the "fade-in" format: a 6-second video that transitions from black to an image. Simple, right? Almost too simple. But the results tell a different story. Average watch time exceeded double the video length, meaning people watched these videos twice on average. The format generated an estimated 200-300 million views across hundreds of posts.
But, here's what makes this counterintuitive. The conversion rates aren't spectacular, and Peter talked about that upfront. But at 300 million views, even modest conversion rates translate into serious user acquisition numbers. The team learned this by watching competitors who understood that volume matters more than perfectionism when you're operating at scale.
"They replicated the same exact video 300 times and it's still working for them," Joseph noted during the interview. Most creators would worry about audience fatigue or algorithm penalties. Stronger proved that if you find something that works, you can milk it far longer than conventional wisdom suggests.
Horizontal scaling and the micro-variant playbook
That said, the team didn't just post the same video 300 times. They built internal tooling to create what they call "micro-variants." Small changes to backgrounds, legend placements, hook wording, and visual elements. The changes had to produce enough variation to help avoid spam hits, while still maintaining the core format that drove the results.
They run multiple accounts using this format, and systematically test these variations using AI and Figma. It's not creative expression, it's manufacturing. The engineering mindset applied to content creation. Test, measure, scale what works, and then they have no qualms killing what doesn't.
Sound selection matters quite a bit here, too. Stronger developed a recognizable brand sound that helps with recall. On TikTok especially, audio can be just as important as visuals for building recognition. Users start associating specific sounds with your brand, creating another layer of stickiness beyond the content itself.
The accidental hard paywall that changed everything
Sometimes the best growth tactics come from bugs. Stronger accidentally implemented a hard paywall overnight when a technical error hit every user opening the app with the paywall. Instead of rushing to fix it, they looked at the numbers. Conversions jumped about 25%.
That bug became a feature (the dream!), and looking at the numbers, they knew that the hard paywall should stay. But Peter's honest about the trade-off: hard paywalls strengthen revenue, but weaken viral loops. When you force payment before value, you reduce social sharing. Users can't evangelize your app to friends if they can't access it.
"You need to choose your strategy clearly: premium monetization or viral social growth," Peter explained. Stronger chose revenue. For their category and business model, the 25% boost in conversions was worth the reduced K-factor. Not every app should make that choice, but they were confident about what they were optimizing for.
Building a heat map that markets itself
The core feature that makes Stronger stand out is their strength visualization heat map. You input your lifts, and it shows you whether you have elite chest strength, novice legs, and how you compare to others at your body weight. It's Strava's approach applied to strength training.
Peter traced the idea back to a viral Twitter thread from six or seven years ago featuring a web app that did something similar. He remembered thinking it was cool, but nobody had built it for mobile. Everyone told them not to build a workout tracker because the space was too saturated. They'd just become a commodity.
The heat map became their differentiation. It wasn't just a product feature, it was their primary marketing asset. The visual is eye-catching, shareable, and instantly communicates value. When users screenshot their progress and share it, they're essentially creating free advertising. This helps combat the previous point about reduced K-factor. If someone does start a trial or convert, the likelihood of them sharing their workout journey is substantially higher than it otherwise might be.
The reply/stitch loop and founder-led content
One of Stronger's most effective tactics is converting viewer comments into tailored video responses. Someone asks a question, and Peter or his co-founders create a video addressing it directly. This "reply/stitch loop" creates ongoing dialogue that feels personal and keeps viewers engaged.
Stronger's first viral moment actually came before they launched. Peter's co-founder Jack created a Canva prototype video showing the concept, and it took off on TikTok. They built a following before they had a product. That founder-led authenticity established credibility that's hard to replicate.
Peter emphasizes that slightly rough, authentic TikTok content consistently outperforms polished ads. Overproduction signals advertising, which triggers skepticism. Authenticity signals a real person sharing something they care about. In an increasingly AI-generated content world, that human presence becomes an edge.
Hunting formats across industries and reverse engineering success
Stronger doesn't just look at fitness content for inspiration. They hunt winning formats across completely different industries, reverse engineer the underlying mechanics, then adapt them.
"Look outside your category," Peter advises. "What formats are working in beauty? In finance? In travel? Then ask why they work and how you can apply those principles to your vertical." This cross-pollination approach reveals formats your competitors aren't using because they're too busy staring at other fitness accounts.
They treat content as a science, not an art. Hooks, funnels, analytics, conversion tracking. As engineers, they apply the same experimentation framework to content that they would to product development.
The copycat paradox and growing the category
Peter has an interesting take on copycats. Initially, they frustrated him. Now he sees them as category validators. Why? Because when someone launches a shameless Stronger clone and people search for it in the App Store, guess who shows up in position two? Stronger, with 100x more reviews and social proof. In short, it's free ASO.
"You're taking a slice of the pie, but you're also massively growing the pie," Peter explains. If you're the category leader, copycats actually help you.
He points to Cal AI as the example. Every food-scanning app copycat reinforces Cal AI's position as the category-defining player. If you think "food scanning app," you think Cal AI. The copycats spend money on ads, drive awareness, and users ultimately download the market leader. Peter's approach now: when competitors launch, he looks for novel features to adopt.
Paywall optimization and the power of macro changes
Stronger uses Superwall to run extensive A/B tests on monetization. Peter's learned that macro changes beat microcopy tweaks.
Beyond the accidental hard paywall discovery, they've tested multi-stage paywalls, video paywalls, and different feature presentations. The key is testing big structural changes, not just button colors. "Don't waste time testing if the button should be blue or green," Peter says. "Test if you should have a hard paywall or a soft paywall."
And remember what we mentioned earlier about hard and soft paywalls. There's tension between monetization and virality. Premium paywalls reduce friend-sharing loops because users can't easily show the app to others. Stronger chose to optimize for revenue over viral growth, but that's a strategic decision based on their category's LTV ceiling. If you need help figuring out how to test paywalls, check out our guide here.
Wrapping up
Stronger's success isn't about stumbling onto one viral video. It's about building systems that manufacture virality repeatedly. The fade-in format. The micro-variant tooling. The reply loop. The founder-led authenticity. These aren't tactics you try once, they're infrastructure you build.
As always, if you're ready to test your paywall, run price tests and more for your app, then you're already in the right spot. Sign up for a free Superwall account today!
