Lobby and Bro by Roger Chen
Rebuilding online social interaction to feel like spontaneous, low-pressure IRL hangouts.
Core Founder Skill
Product Type
Business Model
Growth & Distribution
Idea Validation Method
Summary
Roger Chen built two viral social apps, Lobby and Bro, both hitting #1 on the App Store. Lobby achieved 500,000 DAU through product-led viral growth by creating a shared experience feature. Bro, an AI companion, validated its concept with mockups and TikTok ads before building, then scaled using TikTok creators.
Founder Moves
Validate Ideas with High-Fidelity Mockups & Paid Ads
Used ProtoPie to create interactive, tappable mockups that felt like a real app.; Tested various app UI/UX concepts using TikTok ads to see what resonated most with potential users.; Utilized ads not for scaling, but as the fastest way to get early feedback and validate product-market fit, especially for consumer social apps.
Before writing a single line of production code, create interactive mockups and test them with targeted paid ads to gauge user interest and identify effective UI/UX.
Product-Led Viral Growth through Shared Experiences
Developed 'Group Picture' feature in Lobby, prompting users to take a photo during video chats, which automatically watermarked and encouraged sharing on social media (Snapchat, Instagram Stories).; Implemented 'one-minute calls' in Lobby as a low-pressure, synchronous interaction point, similar to BeReal's timed posts, to boost temporal density.; Obsessed over increasing network density, recognizing that higher friend connections within the app led to significantly better retention and viral growth.
Integrate features that naturally encourage users to invite friends and share their in-app experiences, focusing on network and temporal density.
Leverage Niche Communities for Initial Seeding & Testing
Lobby unexpectedly went viral in Israel, demonstrating the power of a concentrated user base for product-led growth.; Identified key metrics like 'percentage of people who got five friends day one' as crucial indicators of potential viral spread within a community.; Understood that once virality is proven in a dense community, the product itself drives further organic growth.
Instead of broad marketing, target specific, dense communities for initial user acquisition and observe natural virality.
Scale with Mass-Produced UGC on Trending Platforms
After validating a specific product UX and scenario (e.g., Bro's AI in texting), recruited 50+ TikTok creators.; Mass-produced many variations of content, understanding that virality is unpredictable and requires high volume testing.; Focused on 'hook and demo' video format, where a relatable scenario (hook) leads to a subtle demonstration of the app's functionality (demo).
Once a compelling product format is validated, mass-produce user-generated content (UGC) with creators on platforms like TikTok to achieve broad reach.