OpenAI just dropped GPT-5.4 Mini and Nano.

Quick take:

Mini matches near-flagship performance at 70% less cost and 2x the speed. Now in ChatGPT, Codex, and the API.

Nano costs $0.20 per million input tokens. API-only, built for agents at scale.

A pipeline that cost $3,000/month on GPT-5.4 could run for ~$250 on Nano.

The real test: whether Mini's 96% tool-calling accuracy holds in production.