OpenAI Rolls Out GPT-5.4 Across ChatGPT, the API and Codex
Story Summary
The new model became OpenAI's mainline reasoning release for professional work, combining recent gains in coding, tool use and long-context tasks.
SAN FRANCISCO ? OpenAI rolled out GPT-5.4 on March 5, making the model available across ChatGPT, the API and Codex in what the company described as its new mainline reasoning release for professional work.
In OpenAI's release announcement, the company said GPT-5.4 combines advances in reasoning, coding and agentic workflows, and that it would replace GPT-5.2 Thinking for many paid ChatGPT users while also shipping as `gpt-5.4` in the API.
Deployment details were echoed in OpenAI's ChatGPT release notes, which said GPT-5.4 Thinking began rolling out the same day in ChatGPT and improved deep web research, long-context work and planning during responses.
The broader release timeline is also reflected in OpenAI's release index, where GPT-5.4 is listed alongside GPT-5.3 Instant and GPT-5.3-Codex as part of the company's rapid 2026 model cycle.
The launch added to the race among major AI labs to position coding and agent-style systems as the default tools for professional software and knowledge work.