Press
WhatCable is a free, open-source macOS menu bar app that tells you what each USB-C cable plugged into your Mac can actually do, and when something's slow, which part of the chain is to blame: the port, the cable, or the device. Built by Darryl Morley. For press enquiries: [email protected]
As featured in
International coverage
- 🇫🇷France: MacGeneration
- 🇩🇪Germany: heise online, t3n, TechBook, iFun.de, Stadt Bremerhaven, BornCity
- 🇮🇹Italy: Spider-Mac, Melamorsicata, IlSoftware.it
- 🇪🇸Spain: Microsiervos
- 🇦🇺Australia: Automatica
About the app
When your Mac charges slowly, or a drive runs at half speed, WhatCable tells you why. It names the weak link in the connection: the Mac port, the cable, or the device on the other end. No swapping cables one at a time to work it out. It reads USB-C cable and port data from the IOKit registry using Apple's public APIs. No root access, no SIP changes, no private entitlements. It reports charging speed, data rate, Thunderbolt and USB4 support, display bandwidth, and e-marker data.
Apple's firmware does the negotiation and publishes the result. It's just not surfaced anywhere in standard macOS tooling. WhatCable reads what's already there, then goes further. It checks the cable's e-marker against what the connection actually negotiated, and on Thunderbolt links, against the controller's own independent hardware measurement of the link speed. So it catches a cable that fails to deliver, and corrects one that under-reports. Plug a 240W Thunderbolt cable into a device that only speaks USB 2.0, and WhatCable won't just show USB 2.0 and leave you guessing. It tells you the device is as fast as it gets, and the cable is fine. Reading the data is the easy bit. Knowing what it means is the product. It is not a physical cable tester and doesn't claim to be. Software can't see inside the jacket, only read what the hardware reports.
No tracking, no telemetry, no background uploads. Free and open source (MIT licence), with 8k stars on GitHub. Available as a direct download or via Homebrew cask, with a bundled command-line tool for scripting and JSON output. Interface and diagnostic verdicts translated into 19 languages. Optional Pro tier at £9.99 one-time, one key covers two Macs. Requires Apple Silicon and macOS 14 or later.
About the developer
Darryl Morley is a self-taught developer based in the UK. He works in e-commerce by day and builds Mac software in his spare time under Bitmoor Ltd. WhatCable started as a tool to answer a question he kept asking himself, which of these identical-looking cables actually does the thing, and turned into something other people wanted too. WhatCable sits alongside WhatPort and WhatBattery, a family of small Mac tools that explain what the hardware is actually doing.
Press kit
- App icon (1024×1024 PNG)
- Download WhatCable (latest release, .zip)
- Source on GitHub
Contact
For press enquiries, or review copies of Pro: [email protected]