Alphabet, the parent company of Internet-server giant Google, has launched a new video-chat application called Duo.

This works with mobile devices running Google’s Android operating system and Apple’s iOS system; it runs on both Wi-Fi and cellular networks.

Duo also uses phone numbers rather than a Google account or G-mail address, making it easier to call friends, family and other people already stored on smartphone contact lists.

The company’s existing video-chat and messaging app, Hangouts, requires a Google account and has achieved limited ‘adoption’, especially in emerging markets.