OpenAI positions GPT-5.5 as the main API model

OpenAI’s API model catalog points developers toward GPT-5.5 as the default starting point for complex reasoning and coding, while GPT-5.6 is listed as available to select trusted partners in preview, with broader availability coming soon. Teams optimizing for latency and cost are directed to smaller variants such as GPT-5.4 mini or GPT-5.4 nano.

The frontier lineup includes GPT-5.5, GPT-5.4, and GPT-5.4 mini, all supporting reasoning levels from none through xhigh and tools including Functions, Web search, File search, and Computer use. OpenAI lists GPT-5.5 at $5 / Input MTok and $30 / Output MTok, with 128K tokens of max output, a 1M context window, and a Dec 1, 2025 knowledge cutoff.

Specialized offerings cover image generation, realtime voice interactions, streaming speech-to-speech translation, speech generation, and transcription. The catalog names GPT Image 2, GPT-Realtime-2, GPT-Realtime-Translate, GPT-Realtime-1.5, GPT-Realtime mini, GPT-Realtime-Whisper, GPT-4o Transcribe, and GPT-4o mini Transcribe among task-specific models.