Yes, the SD card is required even with a very small capacity (i.e. 8GB) for event video/picture buffering. The detail of SD card usages is stated below:
First of all, the major function of Live Video Streaming Does NOT require an SD card, since the connection between the device and cloud has been already established when the streaming starts.
The SD card is for back-up and video buffering purpose. All event-based video recordings do need an SD card for video/picture buffering. It is generally in an unforeseen and sudden situation when there is an event, (for example, the car collides with another car) the video channel is starting built after the event happens, (needs approximately 3 seconds), the video/pictures recorded during the video channel establishment (our rule of recording also includes 2–3 seconds before the event) will be stored into the SD card first, then uploaded to the Cloud Storage. Upon the completion of cloud uploading (depending on network speed. For a 15 seconds event video clip, there is a ~3 seconds overhead buffer followed by simultaneous recording and uploading and visible contents upon finish), all videos are stored in Cloud even if the power is cut or SD card is destroyed.
The camera is in fact recording 24/7 when it is powered on, with all running time videos (including all event videos/pictures) iteratively backed-up into the SD card (when the SD card is full, first in, first deleted). Just in case if something happens but does not trigger an event (including capturing accident of other vehicles on the road with no self involvement) the video clips can be found. If the vehicle enters an area with no 4G/LTE network coverage and an accident happened or, a serious accident that suddenly destroys the power supply system for the vehicle or even the Hub, the video can still be found (the camera will keep recording for ~3 seconds after power interruption to finish the recording).
We believe that having a local back-up for fail-safe is a good and key feature.
Please insert a high-quality Micro SD card with class10 or above from authentic provider/manufacture. The camera support up to 64GB SD card (or 128GB in FAT32 Format).