Premium reasoning model with extended compute for maximum reliability and comprehensive tool access. Designed for challenging problems where accuracy matters more than speed, featuring the highest level of reasoning performance in the o3 family.
- Extended reasoning capability thinking longer to provide the most reliable and detailed responses
- Maximum reliability standard excelling in domains requiring highest accuracy and precision
- Comprehensive tool access with web search, file analysis, visual reasoning, and Python execution
- Expert-validated performance consistently preferred by reviewers across science, education, and programming
- Premium problem-solving ideal for challenging questions where waiting for quality is worthwhile
Web Search
Search the web for current info.
JSON Mode
Output responses in valid JSON format.
Image Generator
Generate images from text prompts.
Model Information
Supported Formats
GPT 5.5OpenAI's most advanced model released April 2026. GPT-5.5 is recommended for most reasoning workloads, combining frontier intelligence with configurable reasoning effort (none → xhigh). Available in API, Codex, and ChatGPT.
GPT 5.5 ProHighest-intelligence API option in the GPT-5.5 family. Use for the most challenging problems that require maximum reasoning depth and can tolerate higher latency. Supports full reasoning effort range from none to xhigh.
GPT 5.4GPT-5.4 is OpenAI's frontier model for complex professional work, designed for agentic, coding, and professional workflows with the highest reasoning capability. Features a 1.05M token context window, native computer use, and built-in support for web search, file search, and MCP.