OpenAI Unveils GPT Codex Alpha for Early User Testing

In the vibe coding, which is an AI-assisted programming technique in which a developer instructs a large language model (LLM) in natural language about what to construct, concentrating on the intended result rather than the code itself, where OpenAI’s Codex is already causing a stir and is about to get even better.

Codex helps you with coding by running in the browser, IDE, and terminal, for those who don’t know.

Codex is more than just a nudge for coding assistance and support. Rather, it can assist you in writing code for a complete website or app.

At the company’s DevDay 2025 next week, OpenAI may reveal some of the new capabilities for Codex that are now being tested.

OpenAI has subtly introduced a new “Codex Alpha” opt-in ahead of the announcement.

Codex Alpha gives you the option to sign up for a new program that grants you early access to features, as seen in the screenshot above.

The feature’s description says, “Get early access to new Codex models and features.”

Despite updating Codex from Windows Terminal, Mayank Parmar a writer was unable to access any more recent models.

Here are the following models that are currently available through Codex:

• Gpt-5-codex low
• Gpt-5-codex medium
• Gpt-5-codex high
• Gpt-5 minimal – fastest responses with limited reasoning; ideal for coding, instructions, or lightweight tasks.
• Gpt-5 low – alances speed with some reasoning; useful for straightforward queries and short explanations.
• Gpt-5 medium – default setting; provides a solid balance of reasoning depth and latency for general-purpose tasks.
• Gpt-5 high maximizes reasoning depth for complex or ambiguous problems.

At OpenAI’s DevDay on October 6, 2025, we should find out more about the Codex Alpha.