What happened
OpenAI released GPT-5.5 and GPT-5.5 Pro to its API, targeting complex professional work. GPT-5.5 supports a 1M token context window, image input, structured outputs, function calling, prompt caching, Batch, tool search, built-in computer use, hosted shell, apply patch, Skills, MCP, and web search, defaulting to medium reasoning effort. GPT-5.5 Pro, designed for tougher problems benefiting from more compute, is available for Responses API requests, including through Batch.
Why it matters
Expanded access to these advanced frontier models for complex professional work provides platform engineers and architects with enhanced capabilities. The 1M token context window and integrated features like tool search and web search allow for more sophisticated applications directly through the API. This follows OpenAI's recent release of GPT-5.4 Mini/Nano models, continuing a trend of expanding model capabilities across the performance spectrum.
