GPT-5.3-Codex Released: 25% Faster Agentic Coding

TL;DR

• GPT-5.3-Codex is live — 25% faster than 5.2 with stronger reasoning and real-time collaboration
• Available now in Codex app, CLI, IDE extension, and Codex Cloud (paid ChatGPT plans only)
• API access coming soon; API users stay on gpt-5.2-codex for now

New

• GPT-5.3-Codex model — Frontier agentic coding performance with improved reasoning, professional knowledge, and 25% faster execution for complex software engineering tasks.
• Real-time collaboration — More frequent progress updates and instant response to steering while the agent works.

How to Switch

• CLI: Start a new thread with codex --model gpt-5.3-codex or use /model during a session.
• IDE extension: Sign in with ChatGPT, then select GPT-5.3-Codex from the model selector in the composer.
• Codex app: Sign in with ChatGPT, then select GPT-5.3-Codex from the model selector in the composer.
• API users: Continue using gpt-5.2-codex until API support launches.

Note

• If GPT-5.3-Codex doesn't appear, update your CLI, IDE extension, or Codex app to the latest version.

Update your Codex tools to the latest version to access GPT-5.3-Codex.

Source: Codex