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System class · No. 06

Voice Agents

AI agents that hold real-time voice conversations for calls, support, and assistants.

29 records · independent index · how we rank

Voice agents hold real-time spoken conversations — answering and placing phone calls, running support lines, and powering assistants — by stitching speech-to-text, an LLM, and text-to-speech together under tight latency budgets. The differentiators are conversational latency and naturalness, telephony and SIP integration, and how gracefully the agent handles the hard parts of real calls: interruptions, silence, background noise, and a clean hand-off to a human when it's out of depth. Sub-second response time is what separates a natural conversation from an awkward one, so scrutinize end-to-end latency, not just the quality of the underlying model. Evaluate the available voices, how well the system handles barge-in when a caller talks over it, and how it manages turn-taking and context across a long call.

Integration surface matters too: check telephony providers, warm transfer to human agents, function calling into your back-end systems, and analytics on call outcomes. Most platforms price per minute of conversation, bundling speech, model, and telephony costs, sometimes with a monthly platform fee on top — so model your real call volume before comparing headline rates. Test with your own scripts, accents, and edge cases rather than the vendor's demo, because voice quality degrades fastest exactly where real callers live: noisy lines, fast talkers, and unexpected questions.

Building one yourself? How to build a voice AI agent

Commercial products

Alphabetical — stars don't measure commercial adoption

Open-source index

→ See the best open-source voice agents, ranked

By language: Python voice agents

Rank by
xiaozhi-esp32-serverInfrastructure本项目为xiaozhi-esp32提供后端服务,帮助您快速搭建ESP32设备控制服务器。Backend service for xiaozhi-esp32, helps you quickly build an ESP32 device control server.JavaScript · 10k stars · MIT · Aug 2026ten-vadSDK / libraryVoice Activity Detector (VAD): low-latency, high-performance and lightweightC · 2.2k stars · Feb 2026bailingAgent百聆 是一个类似GPT-4o的语音对话机器人,通过ASR+LLM+TTS实现,集成DeepSeek R1等优秀大模型,接入openClaw,真正的个人语音助手,时延低至800ms,Mac等低配置也可运行,支持打断Python · 1.8k stars · MIT · Apr 2026CyberVersePlatformSelf hosted, real-time digital human agent platform. Build voice-first AI agents with WebRTC, persona memory, tools, RAG, and optional digital-human video.Python · 1.6k stars · GPL-3.0 · Aug 2026RCLIAgentTalk to your Mac, query your docs, no cloud required. On-device voice AI + RAGC++ · 1.5k stars · MIT · Mar 2026PatterSDK / libraryOpen-source voice-AI SDK. The Vapi/Retell alternative for builders who want to own the stack.Python · 1.0k stars · MIT · Aug 2026rustpbxInfrastructureA PBX written by rustRust · 745 stars · MIT · Aug 2026echokit_serverPlatformOpen Source Voice Agent PlatformRust · 590 stars · GPL-3.0 · Feb 2026StarmoonFrameworkA conversational, AI device + software framework for companionship, entertainment, education, healthcare, IoT applications, and DIY robotics.TypeScript · 549 stars · GPL-3.0 · Mar 2026JARVISAgentYour own personal voice assistant: Voice to Text to LLM to Speech, displayed in a web interfacePython · 525 stars · GPL-3.0 · Jun 2024deepgram-python-sdkSDK / libraryOfficial Python SDK for Deepgram.Python · 457 stars · MIT · Aug 2026bolnaAgentEnd-to-end platform for building voice first multimodal agentsPython · 431 stars · MIT · Oct 2024
Signal inventory open — put your agent in front of people choosing oneReserve a signal slot →
xybridSDK / libraryBuild apps powered by on-device AIRust · 412 stars · Apache-2.0 · Aug 2026ai-avatar-systemAgentAI Avatar / digital human platform — upload a photo, clone a voice, talk to any face in real time with lip-sync video. Open-source, self-hosted. Claude · Whisper · Chatterbox · MuseTalk.Python · 412 stars · MIT · Jul 2026sutandoAgentMy AI Stand. Realtime by day, rewriting itself by night. Summon my AI superpower.Python · 374 stars · MIT · Aug 2026agent-second-brainAgentAn always-on second brain you talk to. Voice notes in Telegram → typed, linked knowledge in your Obsidian vault. Runs 24/7 on the Claude subscription you already have.Python · 352 stars · MIT · Aug 2026LLMVoXSDK / libraryLLMVoX: Autoregressive Streaming Text-to-Speech Model for Any LLMPython · 309 stars · May 2025deepgram-js-sdkSDK / libraryOfficial JavaScript SDK for Deepgram.TypeScript · 271 stars · MIT · Aug 2026M.I.L.E.SAgentM.I.L.E.S, a GPT-4-Turbo voice assistant, self-adapts its prompts and AI model, can play any Spotify song, adjusts system and Spotify volume, performs calculations, browses the web and internet,Python · 234 stars · MIT · Jul 2026gdansk-aiAgentFull stack voice chatbotTypeScript · 199 stars · GPL-2.0 · Oct 2024active-callAgentA SIP/WebRTC voice agentRust · 186 stars · Aug 2026axiom-voice-agentAgentRun a <400ms latency Voice Agent on just 4GB VRAM. Fully offline, no API keys required. Optimized for GTX 1650 and edge robotics with zero-copy inference. (Apache 2.0)Python · 142 stars · Apache-2.0 · May 2026BentoVoiceAgentAgentBuild Phone Calling Voice Agent fully powered by open source models.Python · 128 stars · Jul 2026AI-Voice-AgentAgentSelf-hosted AI voice agentPython · 37 stars · MIT · Jul 2026

Frequently asked

What is a voice AI agent?
A voice agent conducts natural, real-time voice conversations — answering and making calls, handling support, or acting as an assistant — by combining speech recognition, an LLM, and voice synthesis.
How do I choose a voice agent platform?
Prioritize conversational latency and naturalness, telephony/SIP integration, interruption handling, and how easily it hands off to a human. Test with your real call scripts.
How much do voice agents cost?
Typically per-minute usage pricing that bundles speech, model, and telephony costs; some platforms add a monthly fee.