Voice-based AI agents are advancing to such a degree that they are now outperforming call centers and beginning to replace human labor in industries from healthcare to retail, according to venture capital firm Andreessen Horowitz. Making voice programmable means AI can now interpret, respond to and act on voiced queries with more accuracy and reliability. Moore said voice AI lets businesses respond to customers 24/7 instead of having to wait until an office is staffed. For consumers, “We believe voice will be the first — and perhaps primary — way people interact with AI.” Last year, voice AI startups raised $2.1 billion, up eightfold from 2023, according to research firm CB Insights. The 2024 bumper crop included ElevenLabs’ $180 million fundraising round. Growth was driven by advances in voice AI models — such as OpenAI’s Realtime API for speech-to-speech applications — that gave a big boost to applications in various use cases. “It’s really in the last 12 to 18 months that we’ve seen AI voice agents performing as well or better than humans,” Alex Levin, co-founder and CEO of voice AI company Regal, told. A year ago, OpenAI unveiled a “voice mode” built on top of GPT-4o that offered real-time voice responsiveness, the ability to be interrupted, and a diversity in emotional tones rather than robotic responses. ElevenLabs followed with Conversational AI in November, with version 2.0 coming out last month. Meanwhile, players like Kyutai and Speechmatics brought real-time, full-duplex conversations into production, Moore said. These models also became more affordable as latency dropped. OpenAI cut GPT-4o API costs by up to 87.5% last December, according to Moore.