Model Tracker
GPT-5.1-Codex
GPT-5.1-Codex is an AI model made by OpenAI. OpenAI released it on 13 November 2025. OpenAI retired it on 23 July 2026. It takes text, image and returns text.
GPT-5.1-Codex is an AI model made by OpenAI. OpenAI released it on 13 November 2025. OpenAI retired it on 23 July 2026. It takes text, image and returns text. Its context window is 400,000 tokens. Its longest answer is 128,000 tokens. Its knowledge cutoff is 30 September 2024.
- Released
- 13 November 2025 — developers.openai.com, read 19 October 2026
- Status
- Not confirmed: two readings disagree: retired and ga
- Takes
- Text, Image — developers.openai.com, read 19 October 2026
- Returns
- Text — developers.openai.com, read 19 October 2026
- Open weights
- Not confirmed: The maker's pages reviewed do not state whether GPT-5.1-Codex has open weights.
- Licence
- Not confirmed: The maker's pages reviewed do not name a licence for GPT-5.1-Codex.
- Context window
- 400,000 tokens — developers.openai.com, read 19 October 2026
- Longest answer
- 128,000 tokens — developers.openai.com, read 19 October 2026
- Knowledge cutoff
- 30 September 2024 — developers.openai.com, read 19 October 2026
- API price, input
- Not confirmed: The current official pricing page does not list GPT-5.1-Codex. Its model page displays an input price but does not print an as-of date; the model is retired, so a current standard API price cannot be confirmed.
- API price, output
- Not confirmed: The current official pricing page does not list GPT-5.1-Codex. Its model page displays an output price but does not print an as-of date; the model is retired, so a current standard API price cannot be confirmed.
- Where
- API — developers.openai.com, read 19 October 2026
- Parameters
- Not confirmed: The maker's pages reviewed do not publish a parameter count for GPT-5.1-Codex.
- Model card
- Not confirmed: two readings disagree: https://developers.openai.com/api/docs/models/gpt-5.1-codex and https://developers.openai.com/api/docs/models/gpt-5.1-codex.md
Benchmarks
Measured by others, not by the maker: each score with the name the measurer gives the model and the setting it ran, its day and its licence.
Arena
- Code Arena (WebDev), GPT-5.1-Codex: 1,337 (1,325–1,349, 5,011 votes), published 18 October 2026
Arena’s leaderboard dataset (lmarena-ai/leaderboard-dataset on Hugging Face), CC BY 4.0: ratings from people’s votes between two anonymous models, as Arena publishes them. Data · CC BY 4.0
Questions
When was GPT-5.1-Codex released?
OpenAI released GPT-5.1-Codex on 13 November 2025.
What is the context window of GPT-5.1-Codex?
The context window of GPT-5.1-Codex is 400,000 tokens, as OpenAI prints it.
What does GPT-5.1-Codex take and return?
GPT-5.1-Codex takes text, image and returns text.
What is the knowledge cutoff of GPT-5.1-Codex?
The knowledge cutoff of GPT-5.1-Codex is 30 September 2024.
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Sources
- GPT-5.1-Codex Model | OpenAI API (read 19 October 2026)
- Changelog | OpenAI API (read 19 October 2026)
- Deprecations | OpenAI API (read 19 October 2026)
- Pricing | OpenAI API (read 19 October 2026)