Model
GPT-5.5 Pro
OpenAI's highest-effort GPT-5.5 tier for the hardest reasoning, research, and long-horizon agent tasks.
Closed sourcereasoningGPT-5.5generally availableReleased 2026-04-231M context128K max outputOpenAIOfficial page
Model metadata
Modalities: text, imageInput: $30.00/MTokOutput: $180.00/MTokAPI ID: gpt-5.5-pro