openai/gpt-5.1-codexGPT-5.1-Codex is OpenAI’s proprietary AI model, released Nov 12, 2025. It costs $1.25/M input and $10/M output tokens, and handles a 400K-token context window. Its strongest use case is math, where it ranks in the 77th percentile of the models Model Beat tracks.
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.
Scores on standardized evaluations. Higher is better — and rank shows where GPT-5.1-Codex lands among all models tracked on Model Beat.
Graduate-level scientific reasoning
Frontier of human expert knowledge
Broad expert knowledge
Contamination-free coding
Scientific research coding
Human-rated web development
Olympiad-qualifier math
Multi-step agentic tasks
Command-line agentic tasks
Tool-agent-user reliability
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.
GPT-5.1-Codex is an AI model developed by OpenAI, part of the GPT family, released Nov 12, 2025.
GPT-5.1-Codex is served from $1.25 per million input tokens and $10 per million output tokens (cheapest credible provider on OpenRouter: Azure).
GPT-5.1-Codex supports a context window of up to 400K tokens.
On standardized evaluations tracked by Epoch AI, GPT-5.1-Codex scores 84.9% on LiveCodeBench, 86.0% on MMLU-Pro, 95.7% on AIME 2024/2025.
GPT-5.1-Codex is a proprietary model (API access), available through its provider's API rather than as a downloadable open-weight model.
Benchmark data from Epoch AI (CC BY) and Artificial Analysis; pricing, specs & descriptions from OpenRouter. Data updated Jul 30, 2026.