OpenPhone develops a reliable smart business phone app that lets users seamlessly get a business phone number without a second phone or a second SIM card. OpenPhone separates a user's business and personal contacts so they can stay in touch with their customers easier. OpenPhone is a VoIP (Voice over Internet Protocol) number provider. This means that all calls and texts happen over the internet through WiFi or mobile data. This functionality is common among second phone number apps, including Google Voice, Burner, and of course OpenPhone was founded in 2018 and based in San Francisco, California.