GPT-5.1 (2025-11-13)
gpt-5.1-2025-11-13Snapshot version of GPT-5.1 for reproducible outputs.
StableReproducibleProduction
Input¥1.80
Output¥15.00
per 1M tokens
Stable
Pinned model version
Reproducible
Consistent results
Production
Ready for deployment
Reliable
Predictable behavior
API Documentation
View complete API reference with all parameters and examples.
Advanced Features
Streaming
Enable real-time streaming responses with Server-Sent Events.
{
"model": "gpt-5.1-2025-11-13",
"stream": true,
"messages": [...]
}Function Calling (Tools)
Enable the model to use tools and call functions.
{
"model": "gpt-5.1-2025-11-13",
"tools": [{
"type": "function",
"function": {
"name": "get_weather",
"description": "Get current weather for a location",
"parameters": {
"type": "object",
"properties": {
"location": {"type": "string", "description": "City name"}
},
"required": ["location"]
}
}
}],
"messages": [{"role": "user", "content": "What's the weather in Tokyo?"}]
}JSON Mode
Get structured JSON responses from the model.
{
"model": "gpt-5.1-2025-11-13",
"response_format": {"type": "json_object"},
"messages": [{"role": "user", "content": "Extract info as JSON: John is 30 years old"}]
}API Parameters Reference
| Parameter | Type | Required | Description |
|---|---|---|---|
| model | string | Yes | Model identifier (e.g., gpt-5.1-2025-11-13) |
| messages | array | Yes | Array of message objects with role and content |
| max_tokens | integer | No | Maximum tokens in the response |
| stream | boolean | No | Enable streaming responses (SSE) |
| temperature | number | No | Sampling temperature (0.0 - 2.0) |
| top_p | number | No | Nucleus sampling threshold (0.0 - 1.0) |
| tools | array | No | Function calling tools definition |
| response_format | object | No | Output format (e.g., json_object) |
Full API Documentation
View complete API reference with streaming, thinking, and more.
Pricing
Input
¥1.80
per 1M tokens
Output
¥15.00
per 1M tokens
Billing: Cost = (input_tokens * input_price + output_tokens * output_price) / 1,000,000