Knock on your group's phones over the same WiFi, and get a reply.
Familiar Knock Knock lets someone in your group knock over the WiFi you share, at home, at a holiday house or with family, so everyone there can hear it and reply: "Coming", "On my way", or a quick voice note.
WiFi in hotels and offices: some networks, such as those in hotels, offices and other secured buildings, block phones from connecting to each other. On these networks your knocks still ring, but replies and voice notes may not get through. Home WiFi, holiday houses and family homes work fully.
A knock or a reply shows which member's phone sent it. It does not verify who is holding that phone, and it is not a security or identification device. Always ask who is at the door before you open it. See the Terms of Use.