Introducing GPT-5.3-Codex
GPT-5. 3-Codex is a Codex-native agent that pairs frontier coding performance with general reasoning to support long-horizon, real-world technical work.
How Ramp engineers use Codex with GPT-5. 5 to review code and ship improvements, allowing them to get substantive feedback in minutes instead of hours.
GPT-5. 3-Codex is a Codex-native agent that pairs frontier coding performance with general reasoning to support long-horizon, real-world technical work.
How engineers at Nextdoor use Codex with GPT-5. 5 to investigate hard-to-reproduce issues, build across platforms, and focus on product outcomes.
Teams use Codex with GPT-5. 5 to ship production systems and turn research ideas into runnable experiments.
Introducing GPT-5. 1-Codex-Max, a faster, more intelligent agentic coding model for Codex.
How Braintrust engineers use Codex with GPT-5. 5 to run experiments and code faster.
Introducing GPT-5 in our API platform—offering high reasoning performance, new controls for devs, and best-in-class results on real coding tasks.
This addendum to the GPT-5 system card shares a new model: GPT-5-Codex, a version of GPT-5 further optimized for agentic coding in Codex. GPT-5-Codex adjusts its thinking effort more dynamically based on task complexity, responding quickly to simple conversational queries or small tasks, while independently working for longer on more complex tasks.
GPT‑5. 3-Codex is the most capable agentic coding model to date, combining the frontier coding performance of GPT‑5.
See how a group of leading developers use GPT-5 for the first time.
Introducing GPT-5. 5, our smartest model yet—faster, more capable, and built for complex tasks like coding, research, and data analysis across tools.
Learn how ChatGPT Codex helps you go beyond chat by automating tasks, connecting tools, and producing real outputs like docs and dashboards.
GPT-5. 1 is now available in the API, bringing faster adaptive reasoning, extended prompt caching, improved coding performance, and new apply_patch and shell tools.