GPT-5.1-Codex
openai/gpt-5.1-codex
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.
Key facts
- Input price
- $1.25 / 1M tokens
- Output price
- $10.00 / 1M tokens
- Context window
- 400K tokens
- Max output
- 128K tokens
- Accepts
- Text, Images
- Returns
- Text
Example: 1,000 requests with 1,000 input and 500 output tokens each would cost about $6.25 (1M input tokens × $1.25 + 0.5M output tokens × $10.00). Estimate your own usage.
Prices are the provider’s own per-token rates with zero markup, from our price list as of Oct 18, 2026. If a call has extra provider charges (images, audio, web search, cached prompts), you pay the reported cost.
Call it from your code
curl https://api.tokenctr.com/v1/chat/completions \
-H "Authorization: Bearer $TOKENCENTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "openai/gpt-5.1-codex", "messages": [{"role": "user", "content": "Hello!"}]}'Works with any OpenAI-compatible SDK: set the base URL to https://api.tokenctr.com/v1. Quickstart
Benchmarks
Artificial Analysis
- Intelligence index
- 23.7
Design Arena
| Category | Rank | Elo | Win rate |
|---|---|---|---|
| Agents: Mobile apps | 18 | 1191 | 53.4% |
| Agents: Full-stack | 30 | 1086 | 44.5% |
| Agents: Web apps | 41 | 1012 | 44% |
| Models: UI components | 44 | 1237 | 60% |
| Models: Data visualization | 52 | 1215 | 55.9% |
| Models: Game dev | 77 | 1141 | 50.5% |
| Models: Code | 82 | 1154 | 54.6% |
| Models: Websites | 82 | 1163 | 56.1% |
Source: Artificial Analysis indexes and Design Arena results as published in OpenRouter’s model data, fetched Oct 15, 2026. Higher is better. Not measured by TokenCenter. See all rankings.