GPT-5.4 mini and nano add smaller tiers for repeated tasks

OpenAI released GPT-5.4 mini and nano on 17 March for workloads where cost and response time matter. Mini supports text and image input, tool use and computer use, with a 400K context window. Its announced API price was $0.75 per million input tokens and $4.50 per million output tokens.

Nano was API-only at $0.20 per million input tokens and $1.25 per million output tokens, targeting classification, extraction and simpler supporting tasks. Mini also appeared in Codex and through ChatGPT’s Thinking route for Free and Go users, with fallback roles on other plans. The smaller models were not interchangeable feature bundles: a team selecting a cheap supporting agent still had to check which tools and input types that specific model could use.