# GPT-5.1-Codex-Max

GPT-5.1-Codex-Max is an AI model released by OpenAI on Nov 19 2025. It has a 400k context window.

## Facts

| Field | Value |
| --- | --- |
| Model | GPT-5.1-Codex-Max |
| Developer | OpenAI |
| Release date | Wednesday, Nov 19 2025 |
| Licensing | Closed |
| Context window | 400k |

## Questions and answers

### When was GPT-5.1-Codex-Max released?

GPT-5.1-Codex-Max was released by OpenAI on Wednesday, Nov 19 2025.

### Who made GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

### What is the context window of GPT-5.1-Codex-Max?

GPT-5.1-Codex-Max has a context window of 400k. That is the maximum amount of input plus output the model can hold in a single request.

### Is GPT-5.1-Codex-Max open source?

No. GPT-5.1-Codex-Max is a closed model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

### What came before and after GPT-5.1-Codex-Max?

OpenAI's previous tracked release was GPT-5.1 on Nov 12 2025, 7 days earlier. It was followed by GPT-5.2 on Dec 11 2025.


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Canonical page: https://aireleasetracker.com/model/openai/gpt-5.1-codex-max
Site index: https://aireleasetracker.com/llms.txt
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.