GPT-5.5 API pricing on EvoLink is $4.00 per 1M input tokens, $24.00 per 1M output tokens, and $0.40 per 1M cached input tokens. For sessions above 272K input tokens, long-context pricing applies at $8.00 input and $36.00 output per 1M tokens. This guide focuses only on GPT-5.5 pricing. If you want the full GPT family comparison, use the