GPT 5.1 Codex Max
Built by OpenAI · United States · openai.com
GPT-5.1-Codex-Max is OpenAI’s 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...
How to use
model: "openai/gpt-5.1-codex-max"
Cap quality here and save
Hard questions go to this model, easy ones drop to something cheaper. Set a savings target (0–0.8) and the router tunes itself until realized savings converge on it.
{ "model": "celon/auto", "celon": { "anchor": "openai/gpt-5.1-codex-max", "savings_target": 0.4 } }
Naming a model directly gets you that model — savings controls don't apply.
Context
Max output
Input $/1M
Output $/1M
Features
Serving providers
Providers
Price, latency, and uptime per provider serving this model. Celon routes each request to the fastest and cheapest of them. Click a row for regions and data policies.
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Performance
Benchmark quality scores, and measured speed per provider.
Quality
At each model's best reasoning effort. Benchmarks it wasn't run on are omitted.
Speed
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