OpenAI has released GPT-5.4 mini and nano, its most capable small models yet, designed for high-volume workloads where speed matters. GPT-5.4 mini significantly improves over GPT-5 mini across coding, reasoning, multimodal understanding, and tool use while running more than 2x faster. It approaches GPT-5.4 performance on SWE-Bench Pro and OSWorld-Verified benchmarks.

GPT-5.4 nano targets tasks where cost and speed are paramount, offering the smallest and cheapest GPT-5.4 variant. Both models excel in coding workflows that benefit from fast iteration, handling targeted edits, codebase navigation, and debugging loops with low latency. GPT-5.4 mini costs $0.75 per 1M input tokens and $4.50 per 1M output tokens, while nano costs $0.20 and $1.25 respectively.

These models shine in scenarios where larger models aren't optimal - coding assistants needing responsiveness, subagents completing supporting tasks quickly, and multimodal applications reasoning over images in real-time. GPT-5.4 mini is available today in the API, Codex, and ChatGPT, while nano is API-only. The models enable developers to compose systems where larger models handle planning and smaller ones execute quickly at scale, marking a significant step in making AI workflows more efficient and cost-effective.