GPT 5.1 Codex Max
LegacyPremiumExtended-context coding model for large codebase operations.
Designed for workspaces requiring deep context understanding across many files. Higher compute budget for the most demanding engineering tasks.
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GPT 5.1 Codex Max is somewhat expensive at $1.25/M tokens input and $10.00/M tokens output. Cached input reads are priced at $0.13/M tokens, making repeated context cheaper. The model supports vision/image input, extended reasoning, a 400K context window.
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Mistral Small 4vs GPT 5.1 Codex MaxFrequently Asked Questions about GPT 5.1 Codex Max▼
When was GPT 5.1 Codex Max released?
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GPT 5.1 Codex Max was released on December 4, 2025.
Who created GPT 5.1 Codex Max?
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GPT 5.1 Codex Max was created by OpenAI.
How much does GPT 5.1 Codex Max cost?
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GPT 5.1 Codex Max costs $1.25/M input tokens and $10.00/M output tokens.
What is GPT 5.1 Codex Max API pricing?
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The GPT 5.1 Codex Max API is priced at $1.25 per million input tokens and $10.00 per million output tokens. You can access GPT 5.1 Codex Max through idapt.app alongside 200+ other AI models in one workspace.
Is GPT 5.1 Codex Max a reasoning model?
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Yes, GPT 5.1 Codex Max is a reasoning model. It can think step-by-step through complex problems before providing an answer, often yielding better results on difficult tasks like math, coding, and multi-step logic.
Does GPT 5.1 Codex Max support image or vision input?
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Yes, GPT 5.1 Codex Max supports vision/image input. You can share images in your conversation and the model will analyze and respond based on their content.
Does GPT 5.1 Codex Max support audio?
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No, GPT 5.1 Codex Max does not support audio input.
What is the context window of GPT 5.1 Codex Max?
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GPT 5.1 Codex Max has a context window of 400K tokens, meaning it can process approximately 300,000 words of context at once.
Is GPT 5.1 Codex Max open source?
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GPT 5.1 Codex Max is a proprietary model developed by OpenAI. The model weights and training data are not publicly available.
What is GPT 5.1 Codex Max good at?
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Based on benchmark data, GPT 5.1 Codex Max excels at: visual analysis and image understanding. It is OpenAI's capable model suitable for a wide range of tasks.
Where can I use GPT 5.1 Codex Max?
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You can chat with GPT 5.1 Codex Max on idapt.app — no separate API key required. idapt is an AI workspace with 200+ models, agents, computers, and tasks. You can also access GPT 5.1 Codex Max through OpenAI's own API or platform.