Every popular React Native video-trimming library bundles ffmpeg: tens of megabytes of binary, a re-encode on every clip that quietly degrades quality, and a dependency on ffmpeg-kit, which was retired in 2025. react-native-lossless-trim takes the opposite path. It trims by stream-copying the encoded frames on the platform's own native APIs - AVAssetExportSession passthrough on iOS, MediaExtractor and MediaMuxer on Android - so the cut is lossless, near-instant, and adds essentially no binary weight. It also fixes the subtle Android audio/video desync that most passthrough trimmers ship with, by rebasing both tracks to a single shared keyframe origin, and documents the iOS-versus-Android precision tradeoff openly instead of hiding it. Shipped as an Expo module with a typed TypeScript API, New Architecture support, an example app, unit-tested timing logic, and CI.