Aqara U400 Now Supports Samsung Home Key: Why This Makes It One of the Best Smart Locks You Can Buy

Smart lock compatibility has been one of the more fragmented corners of the smart home market. Apple Home Key, which allows iPhone and Apple Watch users to unlock compatible locks by tapping their device against the lock’s NFC reader, was a significant step forward in smart lock convenience when it launched. Samsung Home Key offers the same capability for Galaxy phone users through the Samsung Wallet ecosystem.

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Most smart locks have supported one or the other, creating a purchasing decision that was implicitly a vote for which phone ecosystem your household uses. Aqara’s U400 has broken that compromise: with its latest firmware update, it supports both Apple Home Key and Samsung Home Key on the same hardware, making it one of the only locks that works seamlessly with either platform’s tap-to-unlock convenience.

What Samsung Home Key Actually Is

Samsung Home Key is the Galaxy equivalent of Apple’s Home Key feature: NFC-based digital key functionality built into Samsung Wallet that allows Galaxy phones and compatible Samsung Galaxy Watch devices to unlock supported locks by tapping against the NFC reader. Like Apple’s implementation, Samsung Home Key uses encrypted NFC communication that is more secure than Bluetooth-based unlock approaches that can be vulnerable to relay attacks.

The addition of Samsung Home Key to the U400 means Galaxy users get the same tap-to-unlock convenience that iPhone users have had since the U400 first launched with Apple Home Key support. For households with mixed iPhone and Android users, or for users considering switching from iPhone to Galaxy, the U400’s dual compatibility removes a real smart home friction point.

How Home Key Works vs. App and Code Unlocking

The practical difference between Home Key unlocking and app-based unlocking is speed and reliability. App-based unlocking requires your phone to be connected to the internet or a local Bluetooth connection, the app to be responsive, and a tap or interface interaction to trigger the unlock command. Home Key unlocking requires only that your phone or watch be near the lock, with the NFC interaction completing the unlock in under a second with no app required and no internet connection needed.

For everyday use, this difference is significant enough that users who have experienced Home Key unlocking consistently report that they would not return to app-based unlocking as their primary method. The combination of speed and not requiring conscious interaction makes entering your home feel more like it did with a physical key than any other digital unlock method.

The Offline Advantage: Home Key works without an internet connection or local hub because the digital key credential is stored on the device and the lock, with NFC handling the local authentication. For smart home users who have experienced the frustration of being locked out because their hub went offline or their internet was down, offline-capable unlocking is a reliability improvement with real-world consequences.

The Aqara U400: Full Feature Overview

Physical Design and Installation

The U400 is a deadbolt replacement lock available in both door handle and deadbolt-only configurations. The exterior keypad is capacitive rather than physical, which gives it a cleaner appearance but requires the surface to be dry for fingerprint-based unlock to work reliably. The interior piece is compact enough for standard US door thickness and the installation process is straightforward for anyone comfortable with basic hardware.

Access Methods

Apple Home Key: iPhone and Apple Watch tap-to-unlock via NFC.

Samsung Home Key: Galaxy phone and Galaxy Watch tap-to-unlock via NFC.

Fingerprint: Up to 100 stored fingerprint profiles with fast optical recognition.

PIN code: Up to 50 stored access codes with scheduling and one-time use options.

Physical key: Traditional key backup for reliability and guest access.

App: Aqara Home app control for remote unlock, access logs, and automation.

Smart Home Integration

Aqara has historically led the smart lock category on smart home integration breadth. The U400 works natively with Apple HomeKit, Google Home, Amazon Alexa, and Samsung SmartThings. Matter over Thread support enables integration with the expanding ecosystem of Matter-compatible smart home controllers.

Automations are where the U400’s integration depth becomes most practically useful: auto-lock when you leave home based on presence detection, trigger lighting scenes when you arrive, provide temporary access codes to guests that expire automatically, and receive notification alerts for all lock and unlock events. These automation capabilities work reliably across all supported platforms.

Who Should Buy the U400 Now

The U400 was already a strong recommendation for Apple HomeKit users who wanted Home Key convenience. The Samsung Home Key addition makes it the clear recommendation for anyone who wants tap-to-unlock convenience regardless of which phone platform they use, households with mixed iPhone and Samsung users, and users who want the most future-compatible smart lock available given its support for both major NFC digital key standards.

Bottom Line: The Aqara U400’s addition of Samsung Home Key support makes it the first smart lock that genuinely serves both major smartphone ecosystems with best-in-class NFC tap-to-unlock convenience. Combined with its broad smart home integration, fingerprint access, and solid build quality, the U400 earns a top recommendation in the smart lock category for 2025.

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Aqara U400 official page

Samsung Home Key compatible devices

Apple Home Key locks list