OpenAI releases new models for its Realtime API
OpenAI has updated its Realtime API with three new model snapshots designed to improve transcription, speech synthesis, and function calling. According to developers, the gpt-4o-mini-transcribe variant significantly reduces hallucinations. For text-to-speech tasks, gpt-4o-mini-tts cuts the word error rate by 35 percent. The gpt-realtime-mini model, which targets voice assistants, follows instructions 22 percent more accurately and improves function calling by 13 percent.
? New audio model snapshots are now live in the Realtime API with improvements to reliability, lower error rates, and fewer hallucinations:
- gpt-4o-mini-transcribe-2025-12-15: 89% reduction in hallucinations compared to whisper-1
- gpt-4o-mini-tts-2025-12-15: 35% fewer word... pic.twitter.com/E8clreR1R0
- OpenAI Developers (@OpenAIDevs) December 15, 2025
OpenAI also explicitly mentioned improvements for Chinese, Japanese, Indonesian, Hindi, Bengali, and Italian.
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