Use WhatsApp account on two devices with the same number
Tips & Tricks: How to use the same WhatsApp account on two different phones at the same time
Even though it is not the most elegant of solutions, it works.
Ashwath Narayana K P
One of the downsides of WhatsApp is that it every WhatsApp account is associated with a single phone number making its use limited to one phone at a time. Because the WhatsApp app on your phone periodically checks for an active phone number and if it doesn't find a match, it will prompt you to re-verify to use it again. Therefore, multi-phone use of the same WhatsApp account on multiple phones usually doesn't work. But there is a simple workaround.
Even though it is not the most elegant of solutions, it works. And it only needs an active internet connection on the second phone and functions even without a SIM card.