Introducing the Realtime API
OpenAI launched a public beta of the Realtime API on Oct. 1, 2024 for all paid developers, using a persistent WebSocket to stream low-latency speech-to-speech interactions with GPT-4o. It supports function calling and interruption handling, priced at $5/1M text input tokens and $100/1M audio input tokens; the post also says audio I/O for Chat Completions would arrive in the following weeks.
Why it matters: Removes the speech-to-text and text-to-speech hops that made voice agents slow.