GPT-5.5 Pro is OpenAI's most advanced reasoning model, built on the GPT-5.5 architecture with extended compute. It features a 1M+ token context window with text and image inputs, using deeper thinking to deliver consistently high-quality answers on the most demanding problems in coding, mathematics, research, and multi-step planning. As the first fully retrained base model since GPT-4.5, it is the optimal choice for professional workflows where accuracy and depth take priority over response time.
OpenAIGPT-5.5 Pro is OpenAI's most advanced reasoning model, built on the GPT-5.5 architecture with extended compute. It features a 1M+ token context window with text and image inputs, using deeper thinking to deliver consistently high-quality answers on the most demanding problems in coding, mathematics, research, and multi-step planning. As the first fully retrained base model since GPT-4.5, it is the optimal choice for professional workflows where accuracy and depth take priority over response time.
OpenAI