Uncover the true capabilities of your USB-C cables and ports on macOS.
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Tracked since2026
0 reviews trackedThe Bottom Line
Entry price
Paid plans only
Biggest pro
Provides highly detailed and accurate USB-C diagnostics directly from IOKit.
Biggest con
Only available for macOS 14+ and Apple Silicon Macs.
TL;DR - WhatCable
- Diagnoses USB-C cable and port capabilities on macOS.
- Identifies bottlenecks in charging and data transfer.
- Provides detailed diagnostics for power users and engineers.
Pricing: Paid only
Best for: Enterprises & pros
What is WhatCable?
WhatCable is a macOS application designed to diagnose and understand the real capabilities of your USB-C cables, ports, and connected devices. It helps users identify bottlenecks in charging speeds and data transfer rates, providing clear insights into whether the cable, charger, Mac port, or device is limiting performance.
The free version offers essential information like cable e-marker data, active transport identification, and basic charging details. WhatCable Pro expands on this with deep diagnostics, including live power metering, detailed Power Delivery (PD) contract inspection, port health counters, and signal-level diagnostics directly from IOKit. It's ideal for engineers, power users, and anyone needing to troubleshoot USB-C connectivity issues on their Apple Silicon Mac.
Available on: macOS
Pros & Cons
Pros
- Provides highly detailed and accurate USB-C diagnostics directly from IOKit.
- Helps identify exact bottlenecks in charging and data transfer.
- One-time purchase for the Pro version with free updates.
- User-friendly interface with a menu bar app and optional detached windows.
- Includes advanced features like CLI monitoring and desktop widgets for power users.
Cons
- Only available for macOS 14+ and Apple Silicon Macs.
- Many advanced diagnostic features are locked behind the Pro version.
- May be overly technical for average users who only need basic information.
Key Features
Charging bottleneck identificationData-speed bottleneck identificationCable e-marker data decodingActive transport identification (USB 2, 3, 4, Thunderbolt, DisplayPort)Engineer mode for IOKit propertiesLive power metering (Pro)Power Delivery (PD) contract inspection (Pro)Cable resistance estimation (Pro)
Pricing Plans
WhatCable Pro
£4.99
- One-time payment, no subscription
- All 13 pro features unlocked immediately
- Works on up to 2 Macs with one key
- Licence key delivered by email instantly
- 7-day offline grace period, no phone-home on every launch
- macOS 14 Sonoma or later, Apple Silicon
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WhatCable FAQ
What is the primary difference between the free and Pro versions of WhatCable?
The free version of WhatCable provides essential information about your USB-C cable's capabilities, such as e-marker data and basic charging details. The Pro version unlocks deep diagnostics, including live power metering, detailed Power Delivery contract inspection, cable resistance estimation, port health counters, and advanced DisplayPort Alt Mode details, offering a comprehensive view of your USB-C ecosystem.
Can WhatCable diagnose issues with Thunderbolt connections, or is it limited to standard USB-C?
Yes, WhatCable can identify Thunderbolt paths and provide information about the Thunderbolt link (generation, lanes, bandwidth). The Pro version also includes a cross-check of the cable's e-marker against the Thunderbolt controller to ensure accurate reporting.
How does WhatCable estimate cable resistance, and what is its practical use?
WhatCable Pro estimates cable resistance using multi-point regression across power samples. This feature is practical for identifying worn, damaged, or marginal cables that might be causing inefficient charging or data transfer, helping users proactively replace faulty cables before they lead to significant problems.
Does WhatCable require any special permissions or background processes to function?
WhatCable is designed as a focused menu bar app built for Apple Silicon Macs. It does not require a helper daemon, uses no private APIs, and performs no background uploads. The Pro features read directly from IOKit without needing root access or additional software.
What kind of information does the 'Liquid detection' feature provide?
The 'Liquid detection' feature in WhatCable Pro shows the status of the Liquid Contact Detection Module (LDCM) sensor per port. This can be particularly useful for diagnosing intermittent charging faults or other issues that might arise if the port has been exposed to liquid.
Source: whatcable.uk