Important: This document may not represent best practices for current development. For current information, see About Apple File System.
Apple File System is a new, modern file system for iOS, macOS, tvOS, and watchOS. It is optimized for Flash/SSD storage and features strong encryption, copy-on-write metadata, space sharing, cloning for files and directories, snapshots, fast directory sizing, atomic safe-save primitives, and improved file system fundamentals.
APFS replaces HFS+ as the default file system for iOS 10.3 and later, and macOS High Sierra and later.
To understand how your app interacts with the file system, read File System Programming Guide.