Network performance is often the hidden startup bottleneck in modern apps that rely on the network. In this session, I’ll share how we, at DeliveryHero, optimized HTTP/2 performance and then adopted HTTP/3 to speed app startup requests for Foodpanda — an app with over 12 million daily app opens. This talk will cover both the technical deep dive (protocol-level improvements, Android integration details) and the practical lessons of rolling out such a change across disparate markets. Key takeaways: * Why startup network requests are often the true bottleneck for “time to usable app.” * Optimizing OkHttp's HTTP/2 performance. * How HTTP/3 and QUIC improve over TCP + TLS in real-world mobile conditions. * Enabling and testing 0-RTT safely at scale. * Practical steps to adopt HTTP/3 on Android using Cronet. * Debugging and measuring network-level startup performance. * Lessons learned from rolling out next-gen protocols to millions of users and pitfalls to avoid.