GPT-5.5, GPT-5.4 and DeepSeek V4: which model should you use right now?
Use GPT-5.5 for high-stakes or ambiguous work, GPT-5.4 as the everyday OpenAI API default, and DeepSeek V4 Pro only where lower cost and review matter more than one-shot quality.
The article explains how to route model choice by task risk, API cost, prompt clarity and review effort.