Download Bookbreaker
Version 0.1.6. Free, no account, and it never sends your record anywhere — the ledger is a SQLite file on your own disk. Run it as the Mac app, or run the same engine from the command line.
The Mac app
The macOS app is signed with a Developer ID and notarised by Apple, so it opens without a warning and without you having to right-click your way past Gatekeeper. It carries the same engine the command line runs — the window does no arithmetic of its own, it asks the engine and shows the answer. It needs a Mac with Apple Silicon (M1 or later).
The command line
The same engine, as a command-line tool for macOS, Linux or Windows. It is pure Python with no third-party dependencies and needs Python 3.9 or newer. Download the wheel (199 KB), or install it straight from here:
pip install https://bookbreaker.bet/releases/overlay-0.1.6-py3-none-any.whl
overlay --helpThat is the whole installation. There is no installer, no signing prompt and no launch agent, because there is no background process — nothing runs unless you type a command.
Check what you downloaded
The wheel's SHA-256 is worth checking against: the build pins its timestamps, and three separate builds of this version produced the same digest. Verify before installing:
shasum -a 256 overlay-0.1.6-py3-none-any.whl| File | Size | SHA-256 |
|---|---|---|
| Bookbreaker-0.1.6.dmg | 8.2 MB | ca56d69e1e235b9316c91aa9a8c299562ff8b3201b07659f0d3218e5576257c7 |
| overlay-0.1.6-py3-none-any.whl | 199 KB | 5b20347fc5d95ff41bc7e99447c9fce1af5534d77c6d48bbca51b3ed91ec9e1b |
| overlay-0.1.6.tar.gz | 326 KB | bcaa3bd2b427c64f027dd18834e3464ed0da7622d1a1306e9572488333ba1568 |
These are read off the files themselves when this page is built. Nothing here was typed in, which is the only arrangement that makes publishing a checksum worth doing.
The tarball's digest identifies this build rather than the source: the packaging tool stamps real file timestamps into it, so rebuilding the same code gives a different hash. Only the wheel reproduces byte for byte, so it is the one to check.
What you get
Every command runs against your own ledger and your own snapshots. There is no server, so there is no account to make and nothing to cancel.
| Command | What it answers |
|---|---|
overlay devig | What four methods say a price is really worth, side by side |
overlay arb | Stakes in round numbers, scored by the worst outcome |
overlay middles | Margin and totals middles against counted finals |
overlay offers | Whether a deposit match clears, given what its rollover allows |
overlay paste | A betslip read into your record, shown before it is written |
overlay portfolio | Exposure, measured correlation, and the next stake it implies |
overlay performance | Your return with the interval around it, and whether it proves anything |
The licence
Free to download and run on as many machines as you control, and free to use to make money — placing bets, sizing them and keeping the proceeds are what it is for, and the licence says so explicitly.
What it does not grant is redistribution: you may not pass it on, sell it, bundle it, or run it as a service for other people. One clause is unusual and deliberate — you may not strip the provenance labelling from its output. A build that removes the measured and prior tags prints the same digits while destroying the only thing that makes them worth reading.
The terms are narrow on purpose, because narrow terms can be widened later and wide ones cannot be taken back. Anything already downloaded stays licensed under the terms it shipped with.
What it refuses to do
It will not log into a sportsbook for you. Account linking means handing a third party your credentials, and no feature is worth that — CSV import and the betslip parser do the same job without asking. It also does nothing about identity, location or device: the anti-limiting work is entirely about the shape of the bet, because everything else is fraud rather than strategy.