GPT-5.3-Codex
GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2.
Specifications
| Lab | OpenAI |
|---|---|
| Context window | 400K tokens |
| Input price | $1.75/1M |
| Output price | $14.00/1M |
| Release | Feb 2026 |
In Depth: GPT-5.3-Codex
Summary
GPT-5.3-Codex is an AI model from OpenAI.
Released in Feb 2026. It currently appears in the Overall category on LMRank and 1 other category. It takes text, image, and file input and produces text output, with a context window of 400K tokens. Input pricing is $1.75 per 1M tokens and output is $14.00 per 1M tokens on OpenRouter.