WhatCable explains cable speed, charging limits, e-marker data, and connected devices in plain English. No more guessing why a cable charges slow or refuses to drive your display.
WhatCable reads the USB-C and USB Power Delivery details macOS already exposes, then turns them into useful labels, charging diagnostics, and port-by-port device context.
See whether the cable, charger, or Mac is limiting the current charge rate, with the negotiated power profile highlighted.
Decode cable speed, current rating, vendor identity, and USB PD capability flags from marked USB-C cables.
Identify USB 2, USB 3, USB4, Thunderbolt, and DisplayPort paths under the physical port where they are connected.
Option-click or enable raw details to reveal the underlying IOKit properties when you need the registry-level facts.
Match storage, hubs, docks, and peripherals back to the port they are using, including the negotiated USB speed.
A focused menu bar app on Apple Silicon Macs. No helper daemon, no private API, no background uploads.
The bundled CLI gives you quick snapshots, structured JSON for scripts, and watch mode when you are swapping cables during testing.
jq for repeatable diagnostics.
--watch.
$ whatcable USB-C Port 1 ✓ Charging well at 96W Cable: 5A, 100W, USB4 40 Gbps Charger: 5V / 9V / 15V / 20V PDOs USB-C Port 2 ! Cable is limiting charging speed Cable: 3A, 60W, USB 2.0 Device: External SSD, USB 10 Gbps
WhatCable is signed, notarised, and ships as a universal app. Requires macOS 14 or later on Apple Silicon.
brew tap darrylmorley/whatcable brew install --cask whatcableView tap on GitHub
Grab the latest .zip from GitHub Releases. Drag WhatCable.app into Applications.