Ringo was an international calling app for smartphones that utilized dedicated phone circuits for making calls.^[3] Ringo used local phone networks instead of the user's smart phone's Internet connection to connect calls.^[4] The caller, but not the called party, downloaded and used the app to make calls.^[5] Apps were available for Android, iOS, and Windows Phone. Ringo launched in 2014 and was available for use in many countries, though not all supported all three calling methods:- callout, callback and WiFi.^[6] Calls could be made to mobile and landline phones in any country.^[7] Ringo was discontinued on March 31, 2021.

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Ringo was developed by start-up Riva FZC, the parent holding company of Ringo.^{[citation needed]}

Ringo allowed users to make calls to any number in any destination worldwide and did not use a web connection for its calls.^[8] Users could purchase top-up credits through the app for Android and Windows Phone and through the website for iOS to make calls.^[9] When a call was made using Ringo, it was connected to a local phone network and assigned a local number. The system then switched the call to connect through submarine cables.^[10] At the receiver's destination country the call was connected to a local network again. Although the call was assigned different local numbers every time it was made, the receiver saw the caller's contact details only.^[11][12]