More details were shared by WhatsApp features tracker WABetaInfo about the flash call feature that was first spotted in WhatsApp beta version 126.96.36.199. Through this method, “WhatsApp will call your phone number and then automatically end the call, verifying that the last phone number in your phone’s log is equal to the number that gives you the 6-digit code. This phone number is always different, so there is no way to trick this method, ensuring a safe experience,” WABetaInfo says.
For this feature to work, WhatsApp will reportedly ask the user for permission to make and manage calls and access the phone’s log. WhatsApp is reportedly working on an introduction for the feature to explain why it needs these permission grants. WABetaInfo reports that WhatsApp won’t use your call history for other purposes. It will only compare the last entry from your call history with the phone number that’s supposed to call you and will not be used for other situations.
Additionally, the features tracker reports that the flash call feature won’t be implemented on WhatsApp for iOS as Apple doesn’t offer any public API to read the call history. Also, this feature is optional, and users can continue logging into WhatsApp confirming the 6-digit code received via SMS or call. This flash call feature is under development and is not enabled in beta yet.