eufy Security Smart Lock FamiLock S3 Max vs Aqara UWB Smart Lock U400: Camera or Ecosystem?

This comparison settles one decision: whether a front door needs a lock with a camera and screen built in, or a slimmer deadbolt that plugs into an existing smart home system. The eufy FamiLock S3 Max bundles a 2K doorbell camera and an internal video screen into the lock itself. The Aqara UWB Smart Lock U400 is a Matter-over-Thread deadbolt built for Apple Home, Alexa, Google and Home Assistant setups. The short answer sits in the table below; the long answer follows.

eufy Security FamiLock S3 Max vs Aqara UWB Smart Lock U400 at a Glance

Product	Key Spec	Best Use	Price Tier
eufy Security FamiLock S3 Max	2K HD doorbell camera with 16GB built-in storage	Households replacing both a deadbolt and a doorbell	Premium
Aqara UWB Smart Lock U400	Matter over Thread, Apple Home Key, fingerprint	Homes already running a Matter or Apple Home setup	Upper mid-range

eufy Security FamiLock S3 Max

Type: Keyless entry WiFi deadbolt with integrated doorbell camera
Security Rating: BHMA Grade 1
Camera: 2K HD doorbell camera
Storage: 16GB built-in
Entry Methods: Palm vein recognition, keyless entry
Display: Internal video screen
Connectivity: WiFi

The FamiLock S3 Max is the more ambitious of the two products. It replaces the deadbolt and the doorbell in one installation, and the internal video screen means a visitor can be seen without reaching for a phone. Palm vein recognition is the headline entry method here — a contactless unlock that does not depend on a fingerprint reading cleanly.

The BHMA Grade 1 rating matters for buyers who care about the hardware itself rather than the software. That is the top tier of the ANSI/BHMA deadbolt standard, so the physical lock is built for residential front doors rather than interior use. The 16GB of built-in storage keeps recordings on the device instead of pushing everything to a subscription cloud, which simplifies ongoing costs.

Trade-off: Bundling a camera, a screen and a lock into one unit means a single point of failure — if the electronics need service, the whole front door setup goes with them.

Check the current price on Amazon

Aqara UWB Smart Lock U400

Type: Keyless entry deadbolt
Protocol: Matter over Thread
Power Source: Rechargeable battery
Ecosystems: Apple HomeKit, Alexa, Google Home, Home Assistant
Entry Methods: Apple Home Key, fingerprint, keyless entry
Color: Black

The U400 takes the opposite approach: it does one job and does it inside whatever smart home system the buyer already runs. Matter over Thread is the important line in the name. Matter is the cross-platform standard, and Thread is a low-power mesh protocol, so the lock talks to a hub rather than relying on WiFi alone.

Apple Home Key support is the feature that will decide this for a lot of households. Tapping a phone or watch to unlock is faster than opening an app, and it works without a fingerprint. The rechargeable battery removes the disposable-cell routine, though it does add a charging task to the calendar. The fingerprint reader covers everyone who does not carry an Apple device.

Trade-off: The U400 assumes a Thread border router and a Matter controller already exist in the home — buyers without that infrastructure are paying for capability they cannot use yet.

Check the current price on Amazon

Side-by-Side: What Actually Separates Them

Feature	eufy FamiLock S3 Max	Aqara UWB Smart Lock U400
Primary role	Lock plus doorbell camera	Lock only
Video	2K HD camera, internal screen	None
Local storage	16GB built-in	None stated in product name
Entry methods	Palm vein, keyless	Apple Home Key, fingerprint, keyless
Protocol	WiFi	Matter over Thread
Power	Not stated in product name	Rechargeable battery
Ecosystem support	eufy ecosystem	HomeKit, Alexa, Google, Home Assistant
Hardware rating	BHMA Grade 1	Not stated in product name
Color	Not stated in product name	Black

The first real difference is scope. The eufy unit is a front-door system: camera, screen, storage and lock in one box. The Aqara unit is a lock that hands video duty to whatever doorbell the home already has. Buyers who have no doorbell, or who want one integrated with the lock, get more from the eufy. Buyers who already have a good doorbell are paying for hardware they will not use.

The second difference is ecosystem philosophy. eufy runs its own app and its own storage, which keeps things self-contained but limits how the lock fits into a broader automation setup. The U400 is built for the opposite: it slots into Apple Home, Alexa, Google or Home Assistant and lets those platforms run the routines. A household deep in Apple Home will find the U400’s Home Key support hard to give up.

The third difference is installation overhead. The eufy needs WiFi at the door and a wired or battery setup for the camera side. The U400 needs a Thread border router and a Matter controller — usually a HomePod, an Apple TV, an Echo or a Home Assistant box. Neither is difficult, but only one of them is likely to already be in place.

Which Should You Buy?

Choose the eufy FamiLock S3 Max if the front door currently has no doorbell camera, the household wants to see visitors on a screen inside the home, and palm vein unlocking appeals more than fingerprint reading. It also suits buyers who prefer local storage over a cloud subscription and who want a Grade 1 rated deadbolt as the foundation.

Choose the Aqara UWB Smart Lock U400 if the home already runs Apple Home, Home Assistant or another Matter-compatible platform, a doorbell is already installed, and the priority is fitting the lock into existing automations. Apple Home Key and the rechargeable battery are the two features that make daily use noticeably smoother.

Choose neither if the door is a rental that cannot be modified, or if the household wants a basic keypad deadbolt without app control — both of these products are more capable, and more expensive, than that job requires.

FAQ

1. Is the eufy FamiLock S3 Max a doorbell and a lock at the same time?
   Yes. The product name lists a 2K HD doorbell camera, an internal video screen and a WiFi deadbolt in one unit, so it covers both roles from a single installation.

2. Does the Aqara U400 need a hub to work?
   It uses Matter over Thread, which requires a Thread border router and a Matter controller — typically a smart speaker, a streaming box or a Home Assistant setup. Without one, the lock cannot join the network.

3. Which lock supports Apple Home Key?
   The Aqara U400 lists Apple Home Key in its product name. The eufy FamiLock S3 Max does not, and relies on palm vein recognition and keyless entry instead.

4. Which one stores video locally?
   The eufy FamiLock S3 Max has 16GB of built-in storage for its camera. The Aqara U400 has no camera, so video storage is not part of its job.

5. Is the eufy lock rated for security?
   The product name lists BHMA Grade 1, the top residential tier of the ANSI/BHMA deadbolt standard. The Aqara U400’s product name does not state a hardware rating.

6. Which lock works with Alexa and Google?
   The Aqara U400 lists HomeKit, Alexa, Google and Home Assistant support. The eufy lock runs on WiFi through eufy’s own app.

7. Which is better for a smart home beginner?
   The eufy, because it works over WiFi without a separate hub. The Aqara rewards buyers who already have a Matter controller in place.

8. Can both locks be used without a key?
   Yes. Both are keyless entry deadbolts, with palm vein recognition on the eufy and fingerprint plus Apple Home Key on the Aqara.

Bottom Line

The eufy Security FamiLock S3 Max wins for households replacing a deadbolt and a doorbell together, and the Aqara UWB Smart Lock U400 wins for homes already built around Matter and Apple Home. Buyers who want one device to cover the whole front door should start with the eufy FamiLock S3 Max; buyers who want the lock to disappear into an existing smart home should start with the Aqara U400.