GPT-5.3-Codex (Generative Pre-trained Transformer 5.3 Codex) is a large language model (LLM) announced and released by OpenAI on February 5, 2026.
It is made as a competitor to Claude's Opus 4.6, focusing on code generation, speed and the ability to search repositories, run terminal commands and at the same time, debug code.
GPT-5.3 Codex is available in the Codex app and on the web; access via API is also planned.
According to OpenAI, GPT-5.3-Codex is the company's "first model that was instrumental in creating itself."
On February 12, 2026, GPT-5.3-Codex-Spark was released in a research preview, which is a smaller version of GPT-5.3-Codex which supports text-only input. , GPT-5.3-Codex is only available for ChatGPT Pro ($200/month) subscribers.
References
External links Official website