The open-source alternatives to Vapi are Pipecat, LiveKit Agents, TEN Framework and Bolna. Pipecat (BSD-2-Clause) and LiveKit Agents (Apache-2.0) are the two with plain open licences, Python frameworks that connect a speech-to-text model, a language model and a text-to-speech model into a live conversation over WebRTC or a phone line. TEN Framework is source available: Apache-2.0 with conditions from Agora that forbid competing deployments. Bolna is MIT and its maintainers say they are looking for help. A team switches when it wants to own the pipeline and choose every model in it.
Vapi, in the vendor's own words: "voice agents for builders" that lets you "build, deploy, and improve voice agents as fast as you ship", by its own description. vapi.ai.
| Project | Openness | Licence | Runs as | Platforms | Self-host | Hosted option | Last release | Stars |
|---|---|---|---|---|---|---|---|---|
| Pipecat | OSI | BSD-2-Clause | pip, CLI | Python 3.11 or later server; client SDKs for JavaScript, React, React Native, Swift, Kotlin, C++ and ESP32 | Yes | Yes | Sep 12, 2026 | 15,594 |
| LiveKit Agents | OSI | Apache-2.0 | pip (Python), npm (the separate AgentsJS repository) | Python server; client SDKs for browsers, Swift, Android, Flutter, React Native, Rust, Node.js, Unity, ESP32 and C++ | Yes | Yes | Sep 15, 2026 | 14,230 |
| TEN Framework | Source available | See LICENSE | Docker Compose, GitHub Codespaces | Docker; Python, Go and Node.js inside; an ESP32-S3 board example | Yes | No | Jul 31, 2026 | 11,130 |
| Bolna | OSI | MIT | Docker Compose, Python library | Docker; Python | Yes | Yes | Sep 16, 2026 | 763 |
Licence, release and star figures read from GitHub on September 16, 2026. Openness labels: The code, and the weights where the project is a model, carry a licence on the OSI approved list. The code is public, and the licence limits what you may do with it. Read the LICENSE file before commercial use. The model weights can be downloaded and run. The training data or code is closed, or the weights carry a restriction the code does not.
A Python framework under BSD-2-Clause, maintained by Daily, for real-time voice and multimodal agents, with the widest provider list on this site and telephony serialisers for Twilio, Telnyx, Plivo, Vonage, Exotel and Genesys.
pip, CLI · Python 3.11 or later server; client SDKs for JavaScript, React, React Native, Swift, Kotlin, C++ and ESP32 · Runs on your own machines · Hosted version available from the maintainers
An Apache-2.0 framework for real-time voice agents that connects any speech, language and voice provider, with semantic turn detection, native MCP tool support, a test framework, and an open-source media and SIP stack it can run on entirely.
pip (Python), npm (the separate AgentsJS repository) · Python server; client SDKs for browsers, Swift, Android, Flutter, React Native, Rust, Node.js, Unity, ESP32 and C++ · Runs on your own machines · Hosted version available from the maintainers
A real-time conversational AI framework from Agora with a visual designer, a SIP extension and turn detection, released under Apache-2.0 plus conditions that forbid competing deployments, which makes it source available rather than open source.
Docker Compose, GitHub Codespaces · Docker; Python, Go and Node.js inside; an ESP32-S3 board example · Runs on your own machines
An MIT voice-agent platform that defines an agent in a JSON file and orchestrates speech to text, a language model and text to speech over websockets, with Twilio and Plivo for phone calls, whose maintainers say they are looking for help.
Docker Compose, Python library · Docker; Python · Runs on your own machines · Hosted version available from the maintainers
Pipecat (BSD-2-Clause, maintained by Daily) if you want the widest list of speech, language and voice providers and telephony serialisers for Twilio, Telnyx, Plivo, Vonage, Exotel and Genesys. LiveKit Agents (Apache-2.0) if you want to run the whole stack including the media server on your own machines, with semantic turn detection and a built-in test framework. Both are Python; LiveKit also has a Node.js version.
Yes. Pipecat has serialisers for Twilio, Telnyx, Plivo, Vonage, Exotel and Genesys and its CLI scaffolds a phone bot. LiveKit Agents works with LiveKit's telephony stack, which includes an open-source SIP service. TEN has a SIP extension and a Twilio example. Bolna supports Twilio and Plivo, with Exotel and Vonage marked coming soon.
Pipecat's README lists over twenty speech-to-text providers, over twenty language model providers, and over thirty text-to-speech providers, including local options like Whisper, Ollama, Kokoro and Piper. LiveKit Agents describes a mix-and-match ecosystem and names OpenAI, Deepgram, Cartesia and Google in its samples. TEN's quick start requires OpenAI, Deepgram and ElevenLabs keys. Bolna routes language models through LiteLLM.
LiveKit Agents says you can run the entire stack on your own servers, including the LiveKit media server, or use LiveKit Cloud. Pipecat runs locally and lists eight transports, of which Daily is one. TEN's documented quick start depends on Agora's real-time service. Bolna runs in Docker with a Twilio or Plivo account and ngrok for calls.
Pipecat (BSD-2-Clause), LiveKit Agents (Apache-2.0) and Bolna (MIT) are, with LiveKit's turn-detection models under a separate model licence. TEN Framework is source available: its licence is Apache-2.0 plus conditions from Agora that forbid hosting on end-user devices and any deployment that competes with Agora's offerings. Only its packages directory is plain Apache-2.0.
LiveKit Agents describes semantic turn detection with a transformer model to reduce interruptions. TEN's ecosystem includes a turn-detection extension for full-duplex conversation. Pipecat lists voice activity detection through Silero and noise reduction providers; its README does not describe interruption handling. Bolna's README does not mention it.
Running one of these inside your own environment, with your own data and your own security rules, is the kind of work Reveneau does. Read how a forward deployed engagement works.