"Write once, run everywhere" is a promise that often breaks down under real-world constraints. At Zattoo, building streaming apps across Android, Apple, and Web meant years of separate native stacks that didn't align and didn't scale. This talk is a case study on how Vega, a React Native-first platform from Amazon, brought us surprisingly close to that goal. The multiplatform landscape is shifting fast. Vega lets React Native run natively on the OS without translation layers. For teams struggling with fragmented codebases and duplicated effort, understanding what's now possible can reshape their platform strategy. Key takeaways: 1. Designing a scalable multiplatform architecture with React Native and Vega 2. Managing platform-specific boundaries 3. How a shared codebase shifts team topology from OS silos to feature-focused teams 4. Practical lessons from shipping a production streaming app across all major ecosystems