OpenAI has released GPT-5.5 — its most capable model yet — marking a decisive shift from single-turn Q&A toward long-horizon agentic workflows.
What's new
GPT-5.5 ships with Codex, a dedicated agentic coding layer that can autonomously write, test, and deploy code across multi-step projects. It also brings stronger deep research, data analysis, and the ability to operate desktop and web software end-to-end without human guidance.
Availability
The model rolled out to ChatGPT Plus, Pro, Business and Enterprise users on April 24, and is accessible via the OpenAI API. Separately, OpenAI expanded its AWS partnership — GPT-5.5 and Codex are now available on Amazon Bedrock, giving enterprises a managed cloud path.
Why it matters
GPT-5.5 is the first OpenAI flagship explicitly designed for agents that work autonomously over hours, not seconds. Combined with its AWS distribution deal, it puts serious pressure on Anthropic's Claude and Google's Gemini in the enterprise agentic market.