WhatCable Pro

Go deeper into every
USB-C port and cable

The free app tells you what your cable can do. Pro shows you what it's doing right now - live power, PD contracts, port health, and signal-level diagnostics straight from IOKit.

See what's included

One-time purchase. Works on up to 2 Macs. macOS 14+ required.

WhatCable menu bar popover showing USB-C port diagnostics
See it in action

Real data from real ports

Every reading comes straight from IOKit. No estimates, no guesswork.

Power Monitor showing live wattage graph over time
Power Monitor
Live watts, voltage, and current per port
Full diagnostics view showing pin diagram, cable identity, port health, and power contract
Port Diagnostics
Pin diagram, port health, PD contract, event trace
DisplayPort Alt Mode diagnostics showing lane allocation and monitor identity
Display Detection
DP lane mapping, device identity, signal routing
Pro features

What Pro unlocks

Everything in the free app, plus deep diagnostics that read directly from IOKit - no extra software, no root access needed.

Live power metering

Real-time watts, amps, and voltage per port. Updates every 2 seconds from the battery controller. See exactly what your cable is delivering right now.

PD contract inspector

See the full negotiated power delivery contract: active voltage and current, all available PDOs decoded with type-aware formatting, and any capability mismatches flagged.

Cable resistance estimation

Multi-point regression across power samples estimates cable resistance in milliohms. Useful for spotting worn or marginal cables before they cause problems.

Port health counters

Lifetime attach/detach events, hard resets, shorts, I2C errors, role swap stats, and FET failures per port. See how a port has been treated over its lifetime.

PD event trace

Decoded protocol-level event history per port. See attach/detach sequences, contract negotiation steps, and hard reset events as they happen.

DP Alt Mode details

Lane count, link rate, tunneled vs native, full EDID with monitor model, manufacturer, and year for any display connected over USB-C.

Raw VDO identity

Full Discover Identity VDOs from SOP and SOP', the cable plug itself. Go beyond the e-marker summary to the raw fields your cable's controller actually reported.

Liquid detection

LDCM sensor status per port. See whether the liquid contact indicator has been triggered on any port - useful for diagnosing intermittent charging faults.

Power monitor window

Dedicated SwiftUI window with live Charts showing watts and voltage over time per port. Pin it while you test a charger or cable under load.

CLI monitor mode

whatcable --monitor streams live power and cable state to your terminal. Pipe it, script it, log it.

Widget power sparkline

Desktop widget shows a live power chart alongside cable status. Glance at your desktop and see charging trends without opening anything.

CC advertisement level

Rp current advertisement level with inferred CC line voltage. See what current level your port's pull-up resistor is advertising to attached devices.

Free vs Pro

What's in each tier

The free app covers everything most people need. Pro is for engineers, power users, and anyone who wants the full picture.

Feature Free Pro
Cable identity
Cable type (active / passive / optical)
E-marker identity (VID/PID, vendor name)
Speed and power ratings from e-marker
Raw VDO identity (SOP and SOP')
Power
Basic charger info (voltage, wattage)
Live power metering (watts, amps, volts)
PD contract details (all PDOs, active RDO)
Cable resistance estimation
CC advertisement level
Port diagnostics
Connection state and orientation
Thunderbolt link info (gen, lanes, bandwidth)
Port health counters (resets, errors, FET failures)
PD event trace
DP Alt Mode details and EDID
Liquid detection sensor status
App and CLI
Menu bar app with popover
Desktop widgets (small / medium / large)
JSON output (whatcable --json)
Power monitor window (live charts)
CLI monitor mode (whatcable --monitor)
Widget power sparkline
Pricing

Simple, one-time pricing

No subscription. Pay once, use it forever. Free updates while Pro is in active development.

WhatCable Pro
£4.99
One-time payment, no subscription
  • All 12 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
FAQ

Common questions

Does this work on Intel Macs?
No. WhatCable requires Apple Silicon (M1 or later). The deep IOKit data sources Pro uses are only exposed by Apple's own port controllers, which aren't present on Intel Macs with third-party Thunderbolt chips.
What macOS version do I need?
macOS 14 Sonoma or later. The free app has the same requirement.
How does activation work?
After purchase, your licence key arrives by email. Right-click WhatCable in the menu bar, click Licence, paste the key, and pro features unlock immediately. The app validates once on activation and once per launch, with a 7-day offline grace period if you're without internet.
Can I use one key on multiple Macs?
Yes. One key works on up to 2 Macs. If you need more, contact support and we'll sort something out.
Is the free version still available?
Yes, always. The free app is open source, on GitHub, and installable via Homebrew. Everything in v0.9.0 and earlier stays free. Pro adds the deeper diagnostics on top.
What if I need a refund?
Get in touch within 14 days of purchase. We'll refund you, no questions asked.

Ready to go deeper?

One-time purchase. Works on up to 2 Macs. Unlocks immediately.