About Kallo
Kallo is a monetizable Flutter SDK that brings native SIP voice calling to mobile apps. It wraps the battle-tested baresip stack behind a small, clean Dart API so product teams can add real phone-grade calling without writing native code.
We built Kallo for companies adding customer-support calling to their Flutter products — where WebRTC bolt-ons fall short and a real SIP client is the right tool. The SDK is distributed as a closed binary and validates its license at runtime, so you always know what is deployed where.
What we focus on
Native call quality, secure transport (TLS + SRTP), and a developer experience that fits naturally into a Flutter codebase.
Where we are
Android and iOS are both production-ready today. License management and usage monitoring run through this portal.
Want to evaluate Kallo for your app?