Hiyd Adds Health Tracking to the Watch You Already Wear
Hiyd has introduced a 2.7 mm thick, 7-gram disc that attaches to the back of a watch to add health tracking. Details were reported Oct. 14, 2026. It syncs to an iOS or Android app. TechCrunch
The company was founded by Salah Batroukh, who spent about seven years as a manufacturing design engineer at Apple. The co-founding team includes Omar Shakir as CTO and Mahamad Charawi as head of software.
Attachment is by microsuction, with no magnets or adhesive. Hiyd states its biometric sensor attaches to the caseback of most mechanical watches. Hiyd The company also states the tracker does not damage the host watch. Hiyd
On the sensing side, the device collects heart rate, heart rate variability, or the variation in time between beats, sleep staging, or time in light, deep and REM sleep, movement, calories burned, and VO2 max estimations, or estimates of how well the body uses oxygen during exercise. Hiyd has said the tracker contains an accelerometer, a motion sensor, and an optical sensor, which uses light to read blood flow. Hiyd video
Data flows to companion apps on iOS and Android, with integration into Apple Health and Google Health. The company states it is building additional integrations such as Strava. The company site is hiyd.ai, where it lists fitness and health tracking with no subscription and a VIP waitlist offering $100 in savings.
The broader context here is the split between watches people keep and sensors people upgrade. Integrated smartwatches update the whole package at once, display, radio, battery and algorithms. A caseback module reverses that. It leaves industrial design, movement and wrist time untouched and tries to make biometrics portable across hosts.
In my view, the engineering questions that will decide this are mechanical and signal-related rather than app-related. An optical sensor needs stable skin coupling, controlled pressure and rejection of motion artifact. Mounting that sensor on another watch case changes height, mass distribution and how the assembly sits during sleep and training. Microsuction solves removability, but long-term hold under sweat, heat and lateral load is where such interfaces earn trust. Power, thermal limits and sync reliability matter in the same way. They determine whether HRV and sleep staging hold up outside controlled testing.
Looking at what this means for software, the choice to sync into Apple Health and Google Health lowers integration cost. It lets Hiyd avoid rebuilding graphs, permissions and export paths that users already rely on, while keeping its own app as the calibration and interpretation layer. No subscription simplifies the message, but it shifts pressure to hardware margin and to sustaining algorithm updates without recurring revenue. If Hiyd can maintain signal quality across varied casebacks and wrists, it opens a path where mechanical watches keep their place and still contribute continuous data. That is a modest change with potentially wide use.
