GPT-5.4 mini ($0.75/M) and GPT-5.4 nano ($0.20/M) Released — Nano Outperforms Previous GPT-5 mini at Max Reasoning Effort

Simon Willison·high signal

OpenAI released GPT-5.4 mini and nano on March 17, purpose-built for high-volume agentic workloads. GPT-5.4 nano is priced at $0.20/M input and $1.25/M output — cheaper than Gemini 3.1 Flash-Lite — while mini is $0.75/M input with 2× throughput over its predecessor and cached input at $0.075/M. Simon Willison benchmarked vision tasks at 0.069 cents/image: 76,000 museum photo descriptions cost $52.44 total, making these the most cost-effective vision-capable models currently available.