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GPT-5.1 Codex

openaiopenai/gpt-5.1-codex

Version of GPT-5.1 optimized for agentic coding in Codex.

Context Length
400K
Max Output
128K
Input Priceper 1M tokens
$1.50/ 1M tokens
Output Priceper 1M tokens
$12.00/ 1M tokens

Modalities

textimage→text

Pricing Breakdown

TypeRate
Input$1.50 / 1M tokens
Output$12.00 / 1M tokens

Supported Parameters

temperaturemax_tokenstop_ptoolstool_choiceresponse_formatreasoningstop

API Usage Examples

Use the global api.therouter.ai endpoint shown below for new integrations; the legacy China accelerated endpoint is retired.

cURL
curl https://api.therouter.ai/v1/chat/completions   -H "Content-Type: application/json"   -H "Authorization: Bearer $THE_ROUTER_API_KEY"   -d '{
    "model": "openai/gpt-5.1-codex",
    "messages": [
      {"role": "user", "content": "Summarize the key points from this input."}
    ]
  }'
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