In this episode of Growth by Design, we sit down with growth product manager Luke Longworth — an early Superwall adopter who's spent years optimizing paywalls and subscription funnels for apps big and small. No copy-this-paywall templates, no silver bullets. Just how experienced operators read the data, prioritize tests, and turn one screen into durable revenue.
The "leaky bucket" trap — converting users who churn a month later
When A/B testing makes sense — and what to do when your traffic is too small
Why understanding the whole business beats any fixed test sequence or "best practice"
Guardrail metrics that stop a "winning" test from quietly hurting the business
The metrics that actually matter: trial starts, proceeds per user, ARPU & LTV
The app-to-web gray zone — Apple, Stripe, and web checkout without tanking conversion
What if the apps posting the best revenue screenshots are the ones nobody actually uses? In this episode of Growth by Design, we sit down with Seth Miller, founder and CEO of Rapchat, who spent 13 years building a consumer music app to 15M+ users and 100M+ raps recorded — then rebuilt the whole operation around AI agents. Drawing on a decade of consumer app building, a Series A, and the decision to get off the VC treadmill, Seth unpacks how to tell when your product has hit its ceiling, why UA-dependent businesses are more fragile than they look, and what changes when agents ship you TestFlights every day.
Hanna Grevelius (CPO at Bruce Studios) on why simpler — even "ugly" — paywalls often outperform polished ones, and how teams get misled by metrics.
Anastasiia Avramenko on scaling an app from 20K to 16M installs with minimal spend — the systems, experiments, and lessons behind sustainable growth.
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