GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks....
| Provider | openai |
|---|---|
| Input price | $1.25 / 1M tokens |
| Output price | $10.00 / 1M tokens |
| Context window | 400k tokens |
| Max output | 128k tokens |
| Modalities | text, image |
| Model ID | openai/gpt-5.1-codex |
A 1,000-token prompt with a 500-token answer on OpenAI: GPT-5.1-Codex costs roughly $0.00625. Use the OpenRouter cost calculator to price your own prompt across 400+ models, or the token counter to measure prompt length first.
PromNest stores your prompt library and lets you run any prompt on OpenAI: GPT-5.1-Codex with your own OpenRouter key — including side-by-side comparison with other models. Browse 1,000+ ready-made prompt templates to start.