Sarucrew operates in one of Japan's most distinctive mobile categories: the online trading-card marketplace, where collectors buy, open, and trade cards through the app. It's a high-intent, high-consideration vertical, and one where an install is only as valuable as the purchase that succeeds it. That shaped the mandate: RZR's primary goal was to acquire high-quality new users — specifically first-time purchasers — and to drive long-term retention and in-app spending, prioritizing users with strong lifetime-value potential rather than installs alone, with performance measured against three KPIs: first-purchase CAC, D1 ROAS, and D7 ROAS.
The bar rose again a few months in, when the client removed view-through attribution (VTA) from the campaign entirely. VTA had been part of the attribution model initially, but was later dropped completely and performance held regardless. RZR maintained results without it, demonstrating the strength of the campaign beyond attribution-assisted numbers.
Sarucrew's iOS UA started with a modest budget to prove the vertical could acquire buyers. On the strength of that early signal, spend scaled fast: roughly 1.67X in the first month, then a further step up to 10X. Throughout the ramp, nearly one in three installs kept converting into a new purchaser.
Target: Launch iOS UA and validate that acquired users convert to first-time purchasers efficiently
Execution highlights:
Roughly 30% of installs converted into new purchasers, proving the vertical could be acquired profitably on iOS before a dollar of scale went in. Performance unlocked the budget to scale.
Target: Grow iOS UA spend aggressively while holding install-to-purchaser conversions steady.
Execution highlights:
iOS UA spend scaled 10X from launch, all while holding the conversion rate steady. The ~30% install-to-purchaser rate held flat through the entire ramp, so new purchasers scaled in lockstep with spend rather than being diluted by it.
Target: Hold the scaled run rate while keeping purchaser conversion and cost efficient
Execution highlights:
Once at scale, the campaign held its steady-state run rate for months with conversion intact. A cautious launch had become a durable, iOS acquisition engine that reliably turns installs into buyers in one of Japan's most specialized verticals.
In the ecommerce vertical, an install is a cost until it becomes a purchase. RZR optimized toward first purchase from day one, which is why ~30% of installs converted to buyers instead of the campaign filling up with non-converting installs.
Every step up in budget was earned against performance. Spend rose 10X in validated increments — 1.67X in the first month, then a further step to steady state — each move tested against purchaser conversion before the next.
The hard part isn't hitting 30% conversion at a small budget, it's holding it while spend scales. RZR did, keeping the rate flat across the entire ramp so purchasers grew with spend rather than lagging it.
Japan's online trading-card market is niche, high-intent, and privacy-restricted on iOS. RZR proved it can be acquired profitably at scale.
RZR didn't just spend more for Sarucrew, it proved a repeatable UA playbook for high-intent ecommerce apps:
Purchaser-first optimization models chased buyers and revenue events, not cheap installs
Earned, validated scale 10X spend growth in measured, performance-tested increments
Conversion discipline ~30% install-to-purchaser rate held flat through the entire ramp
iOS in a hard market profitable acquisition in Japan's privacy-restricted, niche collectibles vertical
A new vertical, proven online trading-card marketplace added to what RZR can scale
Case Study
Ella Yang, VP @DHgate
Case Study
Masha Astapkovich, Head of UA, Highcore Games
Case Study
— Nick He, Head of Performance Marketing, Mars Games
Case Study
서혜강 (Hyegang Seo), Actionfit UA 총괄
Case Study
- MARTIN BOCCARDI, SENIOR PERFORMANCE MARKETING MANAGER @ ROVIO
Get cutting-edge insights on retention-led growth straight to your inbox.
