macFUSE 5.0 supports multiple APIs for mounting file systems.

By default, macFUSE uses the VFS API to mount file systems. When specifying the mount-time option -o backend=fskit, macFUSE will use FSKit to mount the file system.

The VFS API is a kernel API for developing file systems. APFS and other Apple file systems are built on the VFS API. Developing a VFS file system requires shipping a kernel extension.

The development of the macFUSE kernel extension started more than a decade ago. It has been maintained, improved and optimized ever since. The macFUSE kernel code is stable and has a proven track record.

FSKit is a user-space API and has been introduced in macOS 15.4. FSKit is a modern successor to the VFS API.

• Using mount points outside of /Volumes is not supported by FSKit.
• Files are always opened in read/write mode.
• The FUSE notification API is not supported, yet.
• Context information (fuse_context_t) is not available due to the information not being provided by FSKit.
• Most mount options previously handled by the kernel are not implemented, yet.
• I/O performance of FSKit volumes is not on par with volumes using the kernel extension backend.