Add real voice calling to your Flutter app
Kallo SDK gives your Flutter app native SIP voice calling — built on baresip, shipped as a closed binary, secured with TLS and SRTP. Perfect for adding customer-support calls to your product.
Everything you need to ship calling
The hard native work is done. You get a clean Dart API and a production-ready binary.
Native SIP, not WebRTC
Kallo wraps baresip for real native SIP voice calling on Android and iOS — registration, outbound and inbound calls, the works.
Built for Flutter
A single Dart API: KalloClient.init(), register(), call(). The native Android (Kotlin) and iOS (Swift) layers are shipped for you as a closed binary.
Call controls included
Mute, hold, and DTMF out of the box, so you can build a real in-app calling experience without touching native code.
Secure by default
TLS signaling and SRTP media transport so voice traffic is encrypted end to end.
Licensed & monitored
Each app validates its license on init. Track usage and subscription time right here in the portal.
Drop-in distribution
Ship as prebuilt native binaries — an Android .aar (arm64-v8a, armeabi-v7a, x86_64) and an iOS xcframework. No native toolchain required on your side.
How it works
From request to your first call in three steps.
Request access
Tell us about your app and use case. We review and send you SDK access.
Get your license key
Create a portal account to receive and manage your KALLO-XXXX license keys.
Ship calling
Add the SDK, call KalloClient.init() with your key, and start placing calls.
Ready to add voice calling?
Request the SDK and create a portal account to manage your license keys and subscription.