OpenAI has launched a version of its latest real-time full-duplex voice model as an API, allowing software developers to implement more responsive voice-enabled apps and conversational workflows.

GPT-Live-1 debuted in July, offering a way to interact through spoken prompts and responses instead of through typed text. Initially available through the ChatGPT interface, the voice model can now be reached via API calls.

As a full-duplex model, GPT-Live-1 can listen and generate speech at the same time, which aids fluid communication. People often talk over one another and may find it frustrating to take turns speaking and listening as if using half-duplex handheld radios.

OpenAI says it has focused on allowing developers implementing GPT-Live-1 to customize how users of business apps experience voice interaction and associated workflows.

"A core GPT‑Live‑1 strength, smooth interruption handling, is already delivering business impact: in early evaluations, Speak found that GPT‑Live‑1 gave learners more time to think before the language tutor responded, cutting interruptions by almost 80 percent versus previous turn-based systems," the company said.

GPT-Live-1 is designed to handle spoken conversation while a backend model (eg, GPT-6 Astra or a more affordable option for rote tasks) handles information lookup, tool usage, and task management.

It represents a step up from OpenAI's Realtime API, which debuted in 2024. In the Tau3 voice-agent intelligence benchmark, which assesses spoken customer-service tasks relevant to airlines, retailers, and telecom companies, GPT-Live-1 scores 86.2 percent, compared to 45.7 percent for GPT-Realtime-2.1 and 42.4 percent for GPT-Realtime-2.

Citing its own evaluations, OpenAI said GPT-Live-1 performs 30 percent better than GPT-Realtime-2.1 in Full Duplex Bench performance, while also outperforming its predecessor in turn-taking latency and interactive behavior.

Yelp has been using GPT-Live-1 for the Yelp Host service, and has nice things to say about the technology as it applies to the company's AI restaurant reservation system. 

"With GPT-Live-1, every call is more conversational and responsive," said Akhil Kuduvalli Ramesh, chief product officer at Yelp, in a statement. "Yelp Host now gives restaurants an advanced voice AI that delivers exceptional guest experiences, captures revenue opportunities they may have otherwise missed, and helps staff focus on serving guests instead of answering the phone."

Yelp does not address whether restaurant customers making reservations welcome the more free-flowing robo-banter or simply accept it because it's better than waiting on hold to chat with a person.

GPT-Live-1 costs $0.05 per minute of usage, on top of whatever backend model is running. Custom voices can be negotiated with the OpenAI sales team. The voice model is also available through OpenAI Presence, the company's enterprise agent platform. ®