AI · alternatives · 2026
24 alternatives to I built a sub-500ms latency voice agent from scratch
I built a voice agent from scratch that averages ~400ms end-to-end latency (phone stop → first syllable). That’s with full STT → LLM → TTS in the loop, clean barge-ins, and no precomputed responses. What moved the needle: Voice is a turn-taking problem, not a transcription problem. VAD alone fails; you need semantic end-of-turn detection. The system reduces to one loop: speaking vs listening. The two transitions - cancel instantly on barge-in, respond instantly on end-of-turn - define the experience. STT → LLM → TTS must stream. Sequential pipelines are dead on arrival for natural…
A voice agent built from scratch that achieves approximately 400 milliseconds of end-to-end latency while running speech-to-text, language model, and text-to-speech in parallel. The system prioritizes turn-taking… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 1 we have checked on their own sites, 1 of them free or with a free tier.
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Our goal with this project is to build a completely open source, state of the art turn detection model that can be used in any voice AI application. I've been experimenting with LLM voice conversations since GPT-4 was first released. (There's a previous front page Show HN about Pipecat, the open source voice AI orchestration framework I work on. [1]) It's been almost two years, and for most of that time, I've been expecting that someone would "solve" turn detection. We all built initial, pretty good 80/20 versions of turn detection on top of VAD (voice activity detection) models. And…
2025 · github.com · its alternatives →
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Hey there, I’m Brian. I've been shipping conversational models over here at Tavus for the past two years. I want to tell you about our new audio-understanding model: Sparrow-2! It’s a new category of model and a unique new approach to conversational audio. Earlier this year we launched Sparrow-1, (at the time) our SoTA turn taking model. Since our Sparrow-1 launch, I’ve spent a lot of time listening to humans talking and trying to really understand how people know when to talk, when to listen, and when to wait. I’ve also been hunting down failure modes of the current SoTA models. And while…
2024 · tavus.io · its alternatives →
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Last year when GPT-4 was released I started making lots of little voice + LLM experiments. Voice interfaces are fun; there are several interesting new problem spaces to explore. I'm convinced that voice is going to be a bigger and bigger part of how we all interact with generative AI. But one thing that's hard, today, is building voice bots that respond as quickly as humans do in conversation. A 500ms voice-to-voice response time is just barely possible with today's AI models. You can get down to 500ms if you: host transcription, LLM inference, and voice generation all together in one place;…
2024 · fastvoiceagent.cerebrium.ai · its alternatives →
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Luke from ElevenLabs here. We just released Scribe Realtime v2, our new real-time Speech to Text model. We rebuilt it from the ground up around a new architecture that uses predictive transcription – it anticipates the next likely word before it’s spoken. That makes it both fast (around 150 ms latency) and highly accurate. Scribe v2 Realtime outperforms every low latency transcription model across 30 commonly used EU and Asian languages – 93.5% accuracy, compared to Gemini 2.5 Flash (91.4%), GPT-4o MiniTranscribe (90.7%), and Deepgram Nova 3 (85%). It supports 90+ languages including…
2025 · elevenlabs.io · its alternatives →
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I've been obsessed for the past ~year with the possibilities of talking to LLMs. I built a bunch of one-off prototypes, shared code on X, started a Meetup group in SF, and co-hosted a big hackathon. It turns out that there are a few low-level problems that everybody building conversational/real-time AI needs to solve on the way to building/shipping something that works well: low-latency media transport, echo cancellation, voice activity detection, phrase endpointing, pipelining data between models/services, handling voice interruptions, swapping out different…
2024 · github.com · its alternatives →
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Voice Agent API▲118One API to build production-ready voice agents
Apr 2026 · assemblyai.com · its alternatives →
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Have a natural, spoken conversation with AI! Contribute to KoljaB/RealtimeVoiceChat development by creating an account on GitHub.
2025 · github.com · its alternatives →
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I wanted to share our new speech to text model, and the library to use them effectively. We're a small startup (six people, sub-$100k monthly GPU budget) so I'm proud of the work the team has done to create streaming STT models with lower word-error rates than OpenAI's largest Whisper model. Admittedly Large v3 is a couple of years old, but we're near the top the HF OpenASR leaderboard, even up against Nvidia's Parakeet family. Anyway, I'd love to get feedback on the models and software, and hear about what people might build with it.
Feb 2026 · github.com · its alternatives →
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Premium AI voice quality without the premium price tag.
2025 · async.com · its alternatives →
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TLDR: We created a personalised Andrej Karpathy tutor that can response to questions about his Youtube videos in sub 1 second responses (voice-to-voice). We do this using a voice enabled RAG agent. See later in the post for demo link, Github Repo and blog write up. A few weeks ago we released the worlds fastest voice bot, achieving 500ms voice-to-voice response times, including a 200ms delay waiting for a user to stop speaking. After reaching the front page of HN, we thought about how we could take this a step further based on feedback we were getting from the community. Many companies were…
2024 · educationbot.cerebrium.ai · its alternatives →
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Hey HN, it’s Russ - cofounder of LiveKit. An open source stack for building realtime AI applications. We’re sharing our first homegrown AI model for turn detection. Here’s a live demo: https://cerebras.vercel.app/ Voice AI has come a long way in the last year. We now have end-to-end systems that can generate a response to user input in 300-500ms — human level speeds! As latency reduces, a common problem that surfaces is the LLM responds too quickly. Any time there’s a short pause in a user’s speech, it ends up interrupting them. This is largely due to how voice AI applications…
2024 · its alternatives →
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Lightning V3▲311Add AI Voice & Chat Agents directly to your website.
Apr 2026 · smallest.ai · its alternatives →
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WhisperFusion builds upon the capabilities of open source tools WhisperLive and WhisperSpeech to provide a seamless conversations with an AI chatbot.
2024 · github.com · its alternatives →
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The most accurate streaming speech model for voice agents.
Mar 2026 · assemblyai.com · its alternatives →
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Fast, accurate STT for production-grade voice agents
May 2026 · ringg.ai · its alternatives →
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KugelAudio▲106Real-time text-to-speech model you can self-host
May 2026 · kugelaudio.com · its alternatives →
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VoiceAI builders can replay production calls (or) create voice test data set and replay those calls to your VoiceAI. With this(https://app.shortloop.dev/) you can now test end to end flows frequently and in an automated way. We have been tinkering with LLMs and building voice applications for the past few months. As we were trying to improve our voice bots performance (interruptions, latency of tts, llm etc) it became very tedious to test our bot over and over again speaking to it. With real users we would observe edge cases that we didn’t handle before. After making changes…
2024 · app.shortloop.dev · its alternatives →
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Voice Activity Detection (VAD) is a crucial component for Voice AI, enabling more natural and efficient interactions. TEN VAD is an open-source solution designed to supercharge your Voice AI Agents with lightning-fast, human-like conversations! TEN VAD offers some key advantages: ONNX Support: Deploy on virtually any platform or hardware architecture! This means greater flexibility and easier integration into your existing systems. Superior Detection Accuracy: Experience noticeable improvements in voice detection, leading to fewer errors and more reliable performance. Smaller & Faster: Enjoy…
2025 · github.com · its alternatives →
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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →