Post by OpenAI Developers on X
OpenAI Developers@OpenAIDevs
XGPT-5.5 is here.
It’s our smartest frontier model yet, introducing a new class of intelligence for agentic coding, computer use, knowledge work, and scientific research.
Rolling out in ChatGPT and Codex today. API is coming soon.
5.5K likes228 repliesPosted Apr 23, 2026