GPT-5.3-Codex
2026 large language model by OpenAI
From Wikipedia, the free encyclopedia
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.[1]
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.[citation needed] In technical benchmarks, it is reported that GPT-5.3 Codex is 25% faster than Opus 4.6.[2]
GPT-5.3 Codex is available in the Codex app and on the web; access via API is also planned.[3]
According to OpenAI, GPT-5.3-Codex is the company's "first model that was instrumental in creating itself."[4][5]
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. As of February 2026[update], GPT-5.3-Codex is only available for ChatGPT Pro ($200/month) subscribers.[6]
