Model BB+Master 128Compact
BBC Micro
A Model B, B+, Master 128 or Compact, cycle-exact. Add a 6502, Z80, ARM or Master 512 second processor, plug ROMs and cartridges into its real sockets, and step through its 6502 in the debugger.
Welcome to
MacBeeb
The BBC Micro, on your Mac. Switch one on and type, play the classics, or wire up a classroom of them on Econet and watch them work together.
Game Library
Elite, Repton, Chuckie Egg, Exile and more: the StarDot community's twenty favourites, set up on the right machine and ready to play. Add your own discs, and Quick Save keeps your place.
Network Studio
A classroom of BBC Micros on Econet, each one running for real: file servers, printers, and messages and programs passed between them. Share the network, and friends join from their own Macs.
Everything a BBC Micro could do, and a few things it couldn't
MacBeeb runs the BBC's own software, Acorn's ROMs and discs included, so it all behaves as it did.
A debugger for 6502 and BBC BASIC
Breakpoints, watchpoints and stepping in the 6502, or in a BASIC program's own lines, with its PROCs, FNs and variables.
Rewind
The machine keeps its last minute. Go back five seconds, or along the timeline, and play on from there; the debugger steps backwards too.
BeebAsm and Baron, built in
MacBeeb assembles your source itself, puts it on a disc and runs it, with breakpoints on your lines. From VS Code too.
Your ROMs, in real sockets
The sockets each model really has, sideways RAM, shadow RAM boards, Master cartridges and VideoNuLA's 4,096 colours.
Econet over the Internet
Send a link or read out a code, and their BBCs join yours on one Econet. Archimedes in MacArch join the same networks.
A Print Centre
Every BBC has a printer, and a network has a printer server. Each job comes out on paper, dot matrix or clean, and as a PDF.
Discs and hard discs
DFS and ADFS, Winchester discs for the Level 3 file server, and the drives' own noises. Drag files in and out in Finder.
Let an AI drive
An MCP server attaches to the running app, so Claude Code or Codex can type, read the screen and debug while you watch.
Gamepads and joysticks
A controller as the BBC's analogue joystick, or on its keys, with mappings that belong to each game's disc.
Built on the work of others
MacBeeb wouldn't exist without three emulators, and the people who wrote them did the hard work: their source, their research into how the real hardware behaves, and their test results.
b2 by Tom Seddon, for the cycle-by-cycle 6502 and much of the machine around it; BeebEm for the Z80, Master 512 and ARM co-processors; and jsbeeb by Matt Godbolt, for the disc drives and timing results to test against.
In a browser, too
MacBeeb's emulation is Swift with no UI attached, and it builds as WebAssembly. The BBC Micro on this site is that build: a Model B or Master 128 with sound, discs, joysticks and Econet, even to Internet Econet rooms.