OpenAI: GPT-5.1-Codex-Max
Analysis Summary
OpenAI GPT-5.1-Codex-Max is a coding-focused variant from OpenAI with a large 400K context window, vision, tool use, and function calling. The OpenAI provenance and broad capability surface are positive signals, but no benchmark data has been published, making it impossible to assess reasoning, coding, or agentic performance objectively.
For businesses, the large context window and multimodal support make it potentially attractive for long-codebase analysis and complex coding workflows. However, without benchmark evidence, it cannot be recommended over proven alternatives in the same price range. At $1.25 input and $10.00 output per million tokens, output costs are high.
Teams should monitor for benchmark releases before adopting this model in production. Until measured performance data is available, established alternatives with published results offer lower risk for business-critical deployments.
Assessed June 6, 2026
Editorial notes
OpenAI GPT-5.1-Codex-Max has vision, tool use, function calling, and a 400K context window, but no benchmark data is available, capping confidence in its real-world capability.
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
Performance Profile
How OpenAI: GPT-5.1-Codex-Max compares
Its 400K-token context window is larger than 85% of the models we list. At $1.25 per million input tokens it is cheaper than 21% of comparable models.
About OpenAI: GPT-5.1-Codex-Max
GPT-5.1-Codex-Max is OpenAIās latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic..
Capabilities
How does OpenAI: GPT-5.1-Codex-Max stack up?
Compare side-by-side with other legacy models.
Model Information
| OpenRouter ID |
openai/gpt-5.1-codex-max
|
| Provider | openai |
| Release Date | December 4, 2025 |
| Context Length | 400,000 tokens |
| Max Completion | 128,000 tokens |
| Status | Active |
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $1.25 | $0.001250 |
| Output | $10.00 | $0.010000 |
Live Performance
Live endpoint metrics, refreshed every 30 minutes.
Leaderboard Categories
External Resources
Frequently asked questions about OpenAI: GPT-5.1-Codex-Max
How much does OpenAI: GPT-5.1-Codex-Max cost?
OpenAI: GPT-5.1-Codex-Max costs $1.25 per million input tokens and $10.00 per million output tokens.
What is the context window of OpenAI: GPT-5.1-Codex-Max?
OpenAI: GPT-5.1-Codex-Max has a context window of 400,000 tokens (400K).
What can OpenAI: GPT-5.1-Codex-Max do?
OpenAI: GPT-5.1-Codex-Max supports image/vision input, tool use, and function calling.
Who created OpenAI: GPT-5.1-Codex-Max?
OpenAI: GPT-5.1-Codex-Max is developed by OpenAI and was released on December 4, 2025.
