telephony

The AI that answers the phone.

Open source voice AI platform. Self-hosted alternative to Vapi and Retell. On Prem, BYOK across Speech to Speech or LLM/STT/TTS, with a visual workflow builder, MCP native and telephony support.

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a versatile software implementation that runs on any commodity hardware. From a Raspberry PI to a multi-core server, FreeSWITCH can unlock the telecommunications potential of any device.

Kamailio - The Open Source SIP Server for large VoIP and real-time communication platforms, focusing on flexibility, security and scalability

Baresip is a modular SIP User-Agent with audio and video support

📱 [Android Library] Get device information in a super easy way.

E2E test framework for tests with complex environment requirements.

Rapida is an open-source, end-to-end voice AI orchestration platform for building real-time conversational voice agents with audio streaming, STT, TTS, VAD, multi-channel integration, agent state management, and observability.

Twilio C#/.NET Helper Library for .NET6+.

MikoPBX — free open-source PBX for small business, built on Asterisk 22, PHP 8.4, and Phalcon 5. Deploy as ISO, Docker, LXC, or in the cloud.

A Java library for communicating with the Twilio REST API and generating TwiML.

📡 A curated list of awesome Real Time Communications resources

An open source Session Border Controller 🌟 The SBC you dream about 🗽 LibreSBC will help you save thousands of dollars.

Modern and flexible SIP/VoIP cli tool

End-to-end platform for building voice first multimodal agents

Add Vonage functionality such as SMS and voice calling to your Laravel app with this Laravel Service Provider.

A complete voice AI building block with telephony integration, featuring real-time speech-to-text, text-to-speech, and LLM-powered conversational agents.

Open-source MCP server for safe, stateful AI-agent phone calls with OpenAI Realtime and Twilio.

T-one is a high-performance streaming ASR pipeline for Russian, specialized for the telephony domain.

Self-hosted, API-first AI call center. Realtime voice bots answer every call, human agents take over without a drop. Full REST + SSE API with OpenAPI spec to embed in your product. FreeSWITCH + OpenAI Realtime / Qwen, one Go binary.