$0.04 a minute: gpt-realtime-2.1 voice agents with reasoning and tool use (2026 build guide)

$0.04 a minute: gpt-realtime-2.1 voice agents with reasoning and tool use (2026 build guide) Summary. On July 6, 2026, OpenAI shipped two speech-to-speech models, gpt-realtime-2.1 and gpt-realtime-2.1