Thread devices are invisible by design. They just work — until one doesn't, and nothing will tell you why. ThreadMapper shows what your devices and your network say about themselves: which devices are on Thread, which border routers you have, which links they report. Nothing it cannot read is shown.
The problem
A sensor stops reporting. An hour later it comes back. Your hub says everything is fine, because from where it stands everything is. The information that would explain it — signal, routing, what else was on the air — is never shown to you at all.
An A–F score with the specific issues pulling it down, not just a number.
Your Thread devices by room, with the links they report. Where no device reported a link, none is drawn.
A device is on Thread when it says so — in its Matter diagnostics or its HomeKit Thread status — never because of its brand. Everything else is listed apart, for what it is.
Offline when it is really gone: a sleepy battery sensor gets two hours, a mains-powered device fifteen minutes, and devices that go quiet together are one alert.
Uptime, reboots and firmware changes for every accessory.
Grade and complications on the wrist; a proper sidebar layout on iPad, not a stretched phone.
Where those tags come from
iOS gives third-party apps no radio signal strength for Thread accessories, no parent-child relationships and no routing table. Any app showing you dBm for a HomeKit device is showing you something it cannot read.
So ThreadMapper shows no signal at all. A device is on Thread when it says so, a border router is one the network proves, and a line on the map is a link a device reported. What the phone can time — how quickly an accessory answers — is shown as exactly that, in milliseconds.
An OpenThread Border Router alone does not fix this.
Its REST API reports real network facts — name, channel, PAN ID — and ThreadMapper uses them. But we tested its diagnostics endpoints against a live two-node mesh: the requests complete and return nothing usable. Per-node routing is not available that way, whatever the documentation implies.
Which is why the probe exists.
The probe
Put our firmware on a small ESP32-C6 board, from a computer's browser, and leave it on a charger. It measures every Thread channel every five minutes, which no phone can, and keeps a day of readings while the app is closed. Where it can join your Thread mesh it reads the mesh from inside, as a real node.
A waterfall of the whole band. You can see the microwave at dinner and the neighbour's Wi-Fi in the evening.
Departures lined up against noise and radio error counters — with the readings shown, and “no clear cause” when there isn't one.
What happened since you last opened the app. Silent when nothing did.
Transmit retries and channel-busy failures — congestion shows here long before anything looks offline.
The board is a Seeed XIAO ESP32C6, about $5–8, and the firmware installs in about ten minutes. The probe is part of ThreadMapper Pro. Setup guide →
Read that first: in a home whose border routers are all Apple's or Google's, the probe can join the mesh only if Home Assistant hands it the credentials. Otherwise it measures the channels and the Wi-Fi on them, and does not read the mesh. It is not a product you can buy — it's a build.
In the app
Privacy
Measurements deliberately don't sync.
Each iPhone and iPad keeps what it saw of your network itself. Merging them would produce a history no single device observed. Notes and settings sync; measurements stay put.
Pro
Field
Field is a one-time purchase for installers, with everything in Pro. Prove The Job walks a visit in seven steps. Keep the customer's readings apart from your own home's, record the network before you touch anything, do the work, record it again as you leave, see the verdict against your own acceptance criteria before the customer does, and hand over the report and a sticker for the hub.
No install needed
Scan a code or open a link and a small slice of ThreadMapper runs without installing the app. It grades a simulated home with the same engine it would use on yours — twelve devices, two border routers, one offline, one on a failing battery — and says before anything else that every number in it is simulated. An App Clip may not read Apple Home or your local network, which is where the real app's numbers come from. Free.
Getting started
A home with at least one Thread border router — a HomePod mini, Apple TV 4K or similar — since ThreadMapper reads your network through HomeKit. The Network Assistant and the troubleshooter need iOS 26 on an Apple Intelligence–capable device; AI Insights works on any iPhone. The probe is entirely optional.
Want to look around first? Turn on Demo Mode and the whole app runs on a simulated network — no hardware, no HomeKit, nothing to set up.
