Mach-O executable file format

A macOS/iOS Mach-O executable, dylib or bundle.

MIME type: application/x-mach-binary
Extensions: .dylib, .bundle, .o
Category: Executables & bytecode

Magic-number signature

0x00000000

CFFAEDFE

····

Mach-O 64-bit LE magic

About the Mach-O executable format

Mach-O is the native binary format of macOS and iOS. A thin 64-bit little-endian binary begins with CF FA ED FE; other magic values cover 32-bit and big-endian variants.

Related formats

Mach-O (universal/fat)
ELF executable
PE (Windows executable)

Have a file that might be Mach-O executable? Identify it with the File Type Identifier — it reads the magic number locally, nothing is uploaded. Or browse all formats.