• What Each Product Actually Is
• The Watch You Wear
• Health Tracking Depth
• Subscription and Data Ownership
• Side-by-Side Comparison
• Who Each Product Is For
• A Note on Where Hiyd Is Right Now
• Frequently Asked Questions

If you own a watch you love and want health data without giving it up, you have probably looked at the Withings ScanWatch Nova. It is one of the few health trackers that actually looks like a watch. But there is a comparison most reviews skip entirely: what happens when you put Hiyd next to it?

These two products share almost nothing in how they approach the problem. That difference is worth understanding clearly.

What Each Product Actually Is

The Withings ScanWatch Nova is a standalone hybrid smartwatch. It replaces whatever you currently wear. It has a traditional dial, an analog display, and health sensors built into the case. Its clinical focus is ECG recording and AFib detection, with additional tracking for sleep, SpO2, and heart rate. It costs around $499, and premium health coaching features require an ongoing subscription.

Hiyd is not a watch. It is a biometric sensor suite that attaches to the back of any watch you already own, using a suction mechanism that leaves no magnets, adhesive, or residue. It sits underneath your watch and tracks continuously throughout the day. Your watch stays exactly as it is.

That structural difference shapes every comparison that follows.

The Watch You Wear

For most people reading this, the watch question is where the decision actually gets made.

The ScanWatch Nova is a well-designed piece of hardware. Withings has put real effort into making it look like a traditional watch. But it is still a specific watch — a specific case size, a specific dial, a specific aesthetic. If you wear a Rolex, a vintage Seiko, a dress watch from an independent maker, or anything with sentimental weight, the ScanWatch Nova does not add to that. It replaces it.

Hiyd adds to it. Press it to the back of any watch and it disappears. You wear what you already wear. Nothing changes on the outside.

For anyone who rotates between multiple pieces, this is not a minor point. Hiyd moves with you from watch to watch. The ScanWatch Nova does not.

Health Tracking Depth

Both products track heart rate and sleep. Beyond that, they diverge significantly.

The ScanWatch Nova's primary clinical differentiator is ECG and AFib detection — a meaningful capability if cardiac monitoring is your specific goal. It also tracks SpO2, breathing disturbances, and general activity. What it does not do is integrate nutrition data or bring sleep, movement, and nutrition together into a single unified view.

Hiyd tracks heart rate, HRV, sleep staging, motion, calories burned, and VO2 max estimation continuously. A silicone band supports dedicated rest and recovery tracking. Nutrition logging is built directly into the companion app — no third-party integration required. All of that data feeds into what Hiyd calls The Reading: a holistic synthesis of sleep, movement, and nutrition in one place.

The Reading does not score you or tell you what to do. It describes. That is a deliberate design choice, and it is different from how every other tracker in this category operates.

If your goal is clinical-grade AFib detection, the ScanWatch Nova addresses that directly. If your goal is a complete, integrated picture of how you are actually living, Hiyd covers more ground.

Subscription and Data Ownership

The ScanWatch Nova hardware costs around $499. Withings' premium health coaching features require an ongoing subscription, and your data lives in their ecosystem.

Hiyd has no subscription at any tier. Your data syncs directly to your phone. Pricing is not publicly listed — the current path is a reservation through the pilot program at hiyd.ai.

If you have grown tired of paying monthly fees for data you already generated, the Hiyd model is a real departure from what the category has normalized.

Side-by-Side Comparison

Who Each Product Is For

The ScanWatch Nova is a reasonable fit if you want a health tracker that looks like a traditional watch, do not have a strong attachment to a specific existing piece, and have a particular interest in ECG or AFib monitoring.

Hiyd is built for a different person. If you already wear a watch you care about, rotate between multiple pieces, want nutrition and biometric data in one place, and have no interest in paying a monthly fee for your own health data — Hiyd addresses all of that without asking you to change anything about how you dress or what you wear.

The core difference is not features. It is philosophy. The ScanWatch Nova asks you to adopt its watch. Hiyd works underneath yours.

A Note on Where Hiyd Is Right Now

Hiyd is currently in its pilot phase. The product is real, the technology is built, and reservations are open. If the problem described here resonates with you, the pilot is where early access begins.

Learn more at hiyd.ai.

Frequently Asked Questions

Can Hiyd attach to a Withings ScanWatch Nova?
Yes. Hiyd attaches to the back of any watch using a suction mechanism, including the ScanWatch Nova. If you already own one and want to add Hiyd's nutrition logging and holistic synthesis layer on top, the two are compatible.

Does Hiyd replace the health tracking in my existing watch?
No. Hiyd adds health tracking to whatever watch you wear. If your watch already has some tracking built in, Hiyd sits alongside it. If it has none, Hiyd provides it — without requiring you to change the watch.

Does the Withings ScanWatch Nova track nutrition?
No. The ScanWatch Nova does not include nutrition logging. Hiyd's companion app includes native nutrition logging, which feeds directly into The Reading alongside sleep and movement data.

Is there a monthly fee for Hiyd?
No. Hiyd has no subscription at any tier. Your data syncs directly to your phone and belongs to you.

What is The Reading?
The Reading is Hiyd's holistic health synthesis. It pulls together sleep staging, movement data, and nutrition logs into one unified view — describing what is happening across your health rather than assigning scores or issuing instructions.

How does Hiyd attach without leaving marks?
Hiyd uses a suction mechanism. No magnets, no adhesive, no residue. It presses on and comes off cleanly.

Who should choose the Withings ScanWatch Nova over Hiyd?
If ECG recording and AFib detection are your primary health goals, the ScanWatch Nova addresses those directly. It is a clinically focused device, and Hiyd does not include ECG capability. For integrative lifestyle health tracking on a watch you already own, Hiyd covers significantly more ground.