Building file transfer applications using Peer-to-Peer Wi-Fi and Bluetooth APIs presents significant challenges due to the differing protocols and capabilities of Android and iOS operating systems, with Android supporting both classic Bluetooth and Bluetooth Low Energy (BLE), while iOS only supports BLE. Developers face difficulties in ensuring cross-platform compatibility and a consistent user experience, as well as technical hurdles like the limited range of peer-to-peer Wi-Fi, the complexities of chunking large files, and the need to maintain reliable connections in the presence of interference. Ditto offers a solution by enabling seamless Bluetooth file synchronization through its Rainbow Connection, which automatically selects the most efficient transport method between P2P Wi-Fi, BLE, and LAN without requiring additional code. Ditto's approach simplifies the integration of Bluetooth file synchronization in apps by providing a straightforward API that includes features like end-to-end encryption, multiplexing, and the ability to handle multiple devices, thereby reducing the need for extensive development and troubleshooting while ensuring secure and efficient file sharing across various platforms.