GPT-5.1

GPT-5.1 is a reasoning and coding model from OpenAI. Call gpt-5.1 through both the OpenAI-compatible Chat Completions API and the Responses API.

Key capabilities

OpenAI-compatible - Works with the OpenAI SDK by changing base_url
Streaming - Real-time token output through SSE
Multi-turn conversations - Uses role-based messages
Responses API - Uses input for text and structured content
Reasoning control - Configure reasoning effort on supported models
Tool use - Supports function and hosted tool definitions

Quick example

Responses API

cURL
Python
Streaming

curl "https://api.mixroute.ai/v1/responses" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.1",
  "input": [
    {
      "role": "user",
      "content": "Explain quantum entanglement in simple terms."
    }
  ],
  "max_output_tokens": 256,
  "reasoning": {
    "effort": "low"
  }
}'

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.mixroute.ai/v1")

response = client.responses.create(
    model="gpt-5.1",
    input="Explain quantum entanglement in simple terms.",
    reasoning={"effort": "low"},
    max_output_tokens=256,
)

print(response.output_text)

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.mixroute.ai/v1")

with client.responses.stream(
    model="gpt-5.1",
    input="Write a short poem about the sea.",
    reasoning={"effort": "low"},
    max_output_tokens=256,
) as stream:
    for event in stream:
        if event.type == "response.output_text.delta":
            print(event.delta, end="")

Chat Completions

cURL
Python
Streaming

curl "https://api.mixroute.ai/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.1",
  "messages": [
    {
      "role": "user",
      "content": "Explain quantum entanglement in simple terms."
    }
  ],
  "max_completion_tokens": 256
}'

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.mixroute.ai/v1")

response = client.chat.completions.create(
    model="gpt-5.1",
    messages=[{"role": "user", "content": "Explain quantum entanglement in simple terms."}],
    max_completion_tokens=256,
)

print(response.choices[0].message.content)

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://api.mixroute.ai/v1")

stream = client.chat.completions.create(
    model="gpt-5.1",
    messages=[{"role": "user", "content": "Write a short poem about the sea."}],
    max_completion_tokens=256,
    stream=True,
)

for chunk in stream:
    print(chunk.choices[0].delta.content or "", end="")

Parameters

Responses API

Parameter	Type	Required	Description
`model`	string	Yes	Must be `gpt-5.1`.
`input`	string \| array	Yes	Text or structured response input.
`max_output_tokens`	integer	No	Maximum output tokens.
`stream`	boolean	No	Enable SSE streaming. Default: false.
`reasoning`	object	No	Reasoning configuration, including effort.
`text`	object	No	Text format and verbosity controls.
`tools`	array	No	Tools the model may call.
`store`	boolean	No	Whether to store the response.

Chat Completions

Parameter	Type	Required	Description
`model`	string	Yes	Must be `gpt-5.1`.
`messages`	array	Yes	Conversation messages with role and content.
`max_completion_tokens`	integer	No	Maximum generated tokens.
`stream`	boolean	No	Enable SSE streaming. Default: false.
`temperature`	number	No	Sampling temperature when supported by the model.
`top_p`	number	No	Nucleus sampling threshold when supported.
`stop`	string \| array	No	Sequences that stop generation.
`tools`	array	No	OpenAI-compatible tool definitions.

Home

Model Introduction

Key capabilities

Quick example

Responses API

Chat Completions

Parameters

Responses API

Chat Completions

​Key capabilities

​Quick example

​Responses API

​Chat Completions

​Parameters

​Responses API

​Chat Completions

Key capabilities

Quick example

Responses API

Chat Completions

Parameters

Responses API

Chat Completions