From the [blog post](https://openai.com/index/introducing-gpt-5-3-codex/#:~:text=GPT%E2%80%915.3%2DCodex%20is%20available%20with%20paid%20ChatGPT%20plans%2C%20everywhere%20you%20can%20use%20Codex%3A%20the%20app%2C%20CLI%2C%20IDE%20extension%20and%20web.%20We%20are%20working%20to%20safely%20enable%20API%20access%20soon.)

> GPT‑5.3-Codex is available with paid ChatGPT plans, everywhere you can use Codex: the app, CLI, IDE extension and web. We are working to safely enable API access soon.

Resolution criteria

GPT-5.3-Codex is currently available with paid ChatGPT plans through the app, CLI, IDE extension, and web. OpenAI is working to safely enable API access soon. This market resolves YES when API access is available for GPT-5.3-Codex, as confirmed by OpenAI's official announcement or developer documentation showing the model accessible via the OpenAI API. Resolution can be verified at OpenAI's API documentation or OpenAI's official blog.

Background

OpenAI launched GPT-5.3-Codex on February 5, 2026, claiming it as the most capable agentic coding model for complex software engineering. The model advances both the frontier coding performance of GPT-5.2-Codex and the reasoning and professional knowledge capabilities of GPT-5.2, together in one model, which is also 25% faster. This is the first launch OpenAI is treating as High capability in the Cybersecurity domain under its Preparedness Framework, activating the associated safeguards.

Considerations

The company is rolling out the model with unusually tight controls and delaying full developer access as it confronts cybersecurity concerns. Full API access is delayed, and high-risk uses are gated behind safeguards, including a trusted-access program for security professionals. The timeline for API availability remains uncertain beyond OpenAI's commitment to enable it "soon."

This description was generated by AI.