OpenAI Realtime API vs Whisper large-v3

Pick two tools from the same category to compare side-by-side.

	OpenAI Realtime API Speech-to-speech realtime model API for building low-latency voice agents.	Whisper large-v3 Open-weights automatic speech recognition (STT) model.
Category	voice	voice
Vendor type	commercial	open source
Pricing	usage	free
Strengths	+ Single model handling speech-to-speech with reasoning and tool calling + Multiple transports including WebRTC, WebSocket, and SIP for telephony + Low-latency persistent sessions for natural turn-taking + Specialized variants for live translation and streaming transcription	+ Open weights; self-host to keep audio in-environment + Strong multilingual transcription accuracy
Tradeoffs	− Locked to OpenAI models with no provider choice − Closed, cloud-only API − Realtime audio pricing can be costly at scale	− Needs a GPU for low-latency, high-volume transcription − Diarization (who said what) requires a separate component
Used in stacks	0	1