GPT-5.5 reasoning
GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...
Capabilities
Context Window 1M tokens
Max Output 128k tokens
Inputs
Outputs
Pricing (per 1M tokens)
Input $5.00
Output $30.00
Cache Read $0.50
Cache Write -
Supported Parameters
include_reasoningmax_tokensreasoningresponse_formatseedstructured_outputstool_choicetools