WhatCable Pro

WhatCable Pro is a macOS in-depth diagnostic tool for USB-C.

Thunderbolt, and charging troubleshooting scenarios that can read real port data directly from IOKit to view power, voltage, current, PD negotiation status, port health, and signal-level details of each USB-C port in real time. It not only recognizes cable type, WhatCable Pro e-marker information, and transmission capability, but also resolves full PD contracts, records event trajectories, estimates cable resistance, and detects the display’s DP Alt Mode, EDID, and link mapping. The software also provides a menu bar interface, independent power monitoring window, desktop widgets, and command-line monitoring modes for flexible switching between daily use, testing, and script recording, making it suitable for engineers, heavy users, and macOS users who need to troubleshoot power supply or connectivity issues.