Yes, you can also use the camera outside the Wi-Fi network without an SD card, as remote access via the eufy Security app works as long as the camera is connected to the Internet. The SD card is only used for local storage of recordings, but is not required for the live stream or the basic function of the camera. The app enables access to the live stream and, if cloud storage is activated, also to recordings saved there. However, without an SD card and without a cloud subscription, no saved recordings are available.