model · OpenAI
OpenAI Realtime API
OpenAI's Realtime API lets an app stream microphone audio straight to the gpt-realtime model and get spoken audio back — no separate transcription or text-to-speech step to wire up yourself. Round-trip latency is typically 150-400ms, so it feels like an actual conversation rather than a walkie-talkie exchange. Under the hood it behaves like a single API even though speech understanding and generation are tightly coupled to the model, which is why tone, interruptions, and back-channel sounds ('mm-hm') come through more naturally than a bolted-together pipeline. It supports function calling mid-conversation, so the agent can look things up or trigger actions while still talking. This is the option to reach for when you want the most polished, least-assembly-required voice agent and don't mind paying a premium and staying inside OpenAI's ecosystem.
What it can help with
- speech-to-text
- text-to-speech
- real-time streaming
- low latency
- voice agent
- function calling
- conversation interface
- audio streaming