OpenAI's Codex is already making waves in the vibe coding vertical, and it's now set to get even better.

For those unaware, Codex runs in Terminal, IDE and web to assist you with coding.

Codex goes beyond the typical nudge for coding help. Instead, it can help you code a full-fledged app or website.

OpenAI is now testing a few new features for Codex, which could be announced at the company's DevDay 2025 next week.

Ahead of the announcement, OpenAI has quietly added a new "Codex Alpha" opt-in.

As you can see in the above screenshot, Codex Alpha allows you to opt into a new program that gives you early access to features.

"Get early access to new Codex models and features," the description of the feature reads.

I updated Codex from Windows Terminal, but I could not get access to any newer model.

Right now, Codex is only giving access to the following models:

• 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

We'll likely learn more about the Codex Alpha at OpenAI's DevDay, which is scheduled for October 6, 2025.