The eufy Security E21 Add-On Camera is a 4K monitor that solves a specific home security puzzle. It’s designed to integrate directly into your existing eufy HomeBase system, providing a high-resolution indoor view without needing a separate hub or subscription. This makes it a straightforward upgrade for anyone already invested in eufy’s ecosystem who wants to keep an eye on a nursery, playroom, or any other indoor space.

The 4K UHD resolution is the clear advantage here. On your smartphone, you can see the weave of a blanket or the gentle rise and fall of a sleeping child’s chest from across the room. The 330-degree pan and 60-degree tilt, controlled smoothly through the app, let you scan the entire area without moving the camera physically. The 8x digital zoom gets you closer, though image quality softens at maximum magnification. A 5000mAh battery offers legitimate portability for temporary placement, and the night vision provides a clear, detailed grayscale image after lights out.

Setup requires a eufy HomeBase (sold separately), which keeps the video feed local and off the cloud for added privacy. The split-screen monitoring in the eufy Security app is genuinely useful for watching multiple rooms at once. Just know its functionality is tied to that HomeBase; this isn’t a standalone Wi-Fi camera. For eufy users looking to expand coverage with a sharp, responsive indoor camera, the E21 delivers a focused and high-performance solution.