PortScope
The cable claims
What the e-marker says
The spec printed on the chip inside the cable, decoded straight from its PD identity, not the box it came in.
The link negotiates
What the two ends trained
The rate your Mac and the device on the other end actually agreed on, which can be lower than the cable's ceiling.
The Mac measures
What really moves through it
Real sustained throughput, tested memory-to-memory or against a drive, so nothing downstream can hide behind a spec sheet.
Features
See it, then prove it
Everything PortScope reads and inspects is free, forever. A single license adds the tools that actively test a cable or a drive, and track them over time.
Free: see everything
No trial timer, no account, no ads
Cable identity
Decode a USB-C cable's e-marker and PD identity: passive or active, per-lane speed, max current and voltage, vendor and cable ID.
Port & device topology
Every physical port and what's plugged into it, with a dock's internal hubs folded into one clean row, or the full chain if you want it.
Live data monitor
Per-device read/write throughput, live network bytes, and DisplayPort lane allocation, all passive, no test required.
Power, four ways
Adapter rating, cable ceiling, negotiated PD contract, and live draw, kept distinct instead of blurred into one number.
"Why is this slow?"
A one-sentence bottleneck verdict that ranks the real causes and names only the one actually holding you back.
Dock bandwidth budget
See exactly how a port's link splits between video and data, and whether a display is stealing from your data lanes.
Reference & glossary
USB and Thunderbolt speed tiers with every marketing rename the same rate has been sold under, the full USB-PD ladder, and a plain-language glossary.
Menu bar quick view
A live tree of everything connected, grouped by hub, with power, throughput, and volume names at a glance.
Licensed: prove it
One license, two Macs, every 1.x update
License
Speed Test
Write and read a real file to measure true sustained throughput, with SLC write-cache sizing, thermal-throttle detection, saved history, and CSV export.
License
Two-Mac Cable Tester
Stream data memory-to-memory between two Macs over the cable under test, so on a Thunderbolt port the cable is the only thing that can be the bottleneck.
License
Cable Health over time
Tracks each cable's link-error counters across sessions, so a cable that's slowly degrading shows itself before it strands you mid-shoot.
License
Wiggle Test
Flex the cable at each end and along its length while PortScope samples link errors at 5 Hz, fast enough to catch a glitch and localize it to a connector.
License
Rename Display
Give a monitor your own name, keyed to its EDID so it sticks across replugs, without ever writing to the display.
Screenshots
A closer look
Speed Test. True sustained throughput, with a live curve against drive temperature.
Cable Tester. Memory-to-memory between two Macs: the cable is the only bottleneck.
Cable Health. Link-error counters tracked over time, so a dying cable shows itself early.
Bandwidth budget. Exactly how a port's link splits between video and data.
Displays. EDID identity, resolution, and DisplayPort lane allocation.
Power contract. Adapter rating, cable ceiling, negotiated contract, live draw: never conflated.
Lives in your menu bar
PortScope stays in the menu bar between checks: a live tree of every connected device grouped by hub, with power, throughput, and volume names at a glance, and an event-driven badge that costs no extra battery.
Pricing
Free to inspect. One license to test.
Every read-only tool (cable identity, port and device topology, power, bottleneck verdicts) is free forever. A single license unlocks Speed Test, the two-Mac Cable Tester, Cable Health, Wiggle Test, and Rename Display.
Free forever to inspect: no account, no ads One license covers two Macs Every 1.x update included, no subscription
Buy a License Download for macOS
Requires Apple Silicon (M1 or later) and macOS 15 Sequoia or newer. Intel Macs aren't supported: their Thunderbolt controllers don't expose cable identity or PD state through any public API.
FAQ
Questions & answers
Do I need a license to use PortScope?
No. The identity and inspection tools (cable identity, port and device topology, live data, power, the bottleneck verdict, and more) are free forever. A license unlocks the five testing tools: Speed Test, the two-Mac Cable Tester, Cable Health, Wiggle Test, and Rename Display.
Can I use it on my laptop and my desktop?
Yes: one license activates on two Macs at once, and you can move a seat between machines any time from Settings.
What happens when version 2.0 comes out?
Your license keeps working with every 1.x release, forever. A future 2.0 would be a separate, optional purchase; nothing you already have stops working.
Does the two-Mac Cable Tester need two licenses?
Each Mac needs an activation. Since one license covers two Macs, a single license is enough if both Macs are yours.
The Cable Tester won't connect to the other Mac
Almost always the wired link between the Macs, not the app: the test needs a live Thunderbolt or USB4 connection straight between them. The Cable Tester troubleshooting guide walks through getting that link up, reading the failure messages, and what a healthy result looks like.
Will it work on my Intel Mac?
No. PortScope requires Apple Silicon (M1 or later) and macOS 15+: Intel Thunderbolt controllers don't expose cable identity or power-delivery state through any public API. That's a hardware limitation, not a missing feature.
Does it send my data anywhere?
No. PortScope runs entirely on your Mac and reads the system's own IORegistry and hardware telemetry. Nothing about your cables, drives, or machine leaves the device; the only network calls it ever makes are the license check and an optional check for app updates.