Rebtel’s free SDK for iOS and Android devs to integrate VoIP calls into their apps has launched with dating app Maybe.

Rebtel tested the functionality in a beta trial with greater than 20 developers, including TGTHR, Agile Dimension, eXeltior, in addition to MobisleApps, creator of the Maybe app. Users will (slightly scarily) be capable to make free anonymous app-to-app calls to potential dates.

The SDK, which matches over wi-fi or 3G, now includes support for iOS background mode and audio playback controls for enjoying ringtones and other sounds.

“Adding free voice functionality is a critical component for our dating app, and we’ve been extremely impressed by both the decision quality and the benefit of integration,” said MobisleApps CEO Fredrik Olofsson. “We think this may be a massive value add for our users who would like to manage to talk with each other anonymously and without charge, while giving us a valuable tool to amass news customers and drive user engagement.”