GPT-5.4 Nano - MixRoute API

GPT-5.4 Nano is OpenAI’s cheapest GPT-5.4-class model for classification, extraction, ranking, and high-volume subagent tasks. Call gpt-5.4-nano through MixRoute using the endpoint below.

Key capabilities

400K context window - Supports substantial input context
128K maximum output - Handles long structured results
Reasoning control - Supports none, low, medium, high, and xhigh
Responses and Chat Completions - Available through both interfaces

Quick example

cURL
Python

curl "https://api.mixroute.ai/v1/responses" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "gpt-5.4-nano",
  "input": "Classify this request and return a short JSON result.",
  "reasoning": {"effort": "low"},
  "max_output_tokens": 256
}'

from openai import OpenAI

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

response = client.responses.create(
    model="gpt-5.4-nano",
    input="Classify this request and return a short JSON result.",
    reasoning={"effort": "low"},
    max_output_tokens=256,
)

print(response.output_text)

Parameters

Parameter	Type	Required	Description
`model`	string	Yes	Model ID. Must be `gpt-5.4-nano`.
`input`	string \| array	Yes	Text or structured response input.
`max_output_tokens`	integer	No	Maximum output tokens.
`reasoning`	object	No	Reasoning configuration, including effort.
`stream`	boolean	No	Enable SSE streaming.
`tools`	array	No	Tools available to the model.

Vendor reference

OpenAI GPT-5.4 Nano model page