OpenAI Responses API Gateway: Models, Pricing & Code

Integrate seven GPT models through APIXO’s OpenAI Responses API gateway. Compare pricing and use copy-ready cURL, JavaScript, Python, or MCP instructions.

Use one OpenAI Responses-compatible integration for all seven GPT models available through APIXO. Configure the APIXO base URL and API key once, then switch models by changing only the model value.

This page includes the complete APIXO model and pricing snapshot verified on July 31, 2026. Model availability and pricing can change, so check the APIXO OpenAI model page before making billing-sensitive decisions.

Choose your integration path: Use the Quickstart to integrate manually, or let an AI implement it by copying this page or using APIXO MCP.

Compare GPT models and pricing

Choose the model that fits the workload, then use its exact model ID in any example on this page.

Model	Model ID	Recommended for	Input	Output	Cache write	Cache read	Savings
GPT-5.5	gpt-5.5	Most complex coding and professional work	$3	$18	$0.3	—	40%
GPT-5.4	gpt-5.4	Complex professional work at a lower cost than GPT-5.5	$1.5	$9	$0.15	—	40%
GPT-5.4 Mini	gpt-5.4-mini	High-volume coding, computer use, and subagent workloads	$0.45	$2.7	$0.045	—	40%
GPT-5.3-Codex	gpt-5.3-codex	Agentic coding in Codex or similar environments	$1.05	$8.4	$0.105	—	40%
GPT-5.2	gpt-5.2	Previous-generation complex professional workloads	$1.05	$8.4	$0.105	—	40%
GPT-5.2-Codex	gpt-5.2-codex	Long-horizon agentic coding on the GPT-5.2 family	$1.05	$8.4	$0.105	—	40%
GPT-5 Mini	gpt-5-mini	Well-defined, cost-sensitive, low-latency, high-volume tasks	$0.15	$1.2	$0.015	—	40%

Prices are in USD per 1 million tokens. — means APIXO does not publish a separate cache-read price for that model. Prices verified: 2026-07-31.

Start with GPT-5.5 when output quality matters most, GPT-5.4 for a lower-cost general-purpose option, GPT-5.4 Mini for efficient high-volume work, a Codex model for agentic coding, or GPT-5 Mini for the lowest-cost well-defined tasks.

What to change

Setting	APIXO value
SDK Base URL	https://llm.apixo.ai/v1
Endpoint	POST /responses
Request URL	https://llm.apixo.ai/v1/responses
API key	APIXO_API_KEY from APIXO API Keys
API key header	Authorization: Bearer $APIXO_API_KEY
Model location	Request body model

Quickstart

export APIXO_API_KEY="your_apixo_api_key"

cURL

curl -X POST "https://llm.apixo.ai/v1/responses" \
  -H "Authorization: Bearer $APIXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.5",
    "input": "Say hello in one sentence."
  }'

JavaScript

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.APIXO_API_KEY,
  baseURL: "https://llm.apixo.ai/v1"
});

const response = await client.responses.create({
  model: "gpt-5.5",
  input: "Say hello in one sentence."
});

console.log(response.output_text);

Python

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["APIXO_API_KEY"],
    base_url="https://llm.apixo.ai/v1",
)

response = client.responses.create(
    model="gpt-5.5",
    input="Say hello in one sentence.",
)

print(response.output_text)

The examples use gpt-5.5. To use any other model in the comparison table, change only the model value.

Let an AI implement it

Copy this page to an AI

Use the Copy page button in the page menu, paste the copied documentation into your AI coding tool, and add this prompt:

Integrate the APIXO OpenAI Responses API into my existing project using the
documentation below.

Requirements:
- Use model gpt-5.5 unless my project already specifies another supported model.
- Read APIXO_API_KEY from an environment variable and keep it server-side.
- Preserve my current language, framework, and project structure.
- Add the smallest working integration and one minimal verification request.
- Do not invent endpoints, model IDs, or request fields that are not documented.

Replace gpt-5.5 in the prompt with any model ID from the comparison table.

Use APIXO MCP

APIXO MCP reads APIXO’s published machine-readable model catalog and schemas; it does not scrape this webpage in real time. The openai-responses schema includes the gateway endpoint, supported model IDs, model guidance, and the pricing snapshot shown above, so an MCP-connected AI can discover the current integration details and write the code for you.

After installing APIXO MCP, ask your AI:

Use the APIXO MCP tools to find the openai-responses model schema. Compare the
supported GPT models and prices, choose the best model for my stated workload,
then integrate the APIXO Responses API into this project. Keep the API key
server-side and add a minimal verification request.

APIXO MCP helps your AI write the integration; it does not replace the API connection used by your application.

Streaming

curl -N -X POST "https://llm.apixo.ai/v1/responses" \
  -H "Authorization: Bearer $APIXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.5",
    "stream": true,
    "input": "Write a short changelog summary."
  }'

Supported OpenAI models

Use one of these exact ids in the request body model field.

• gpt-5.5
• gpt-5.4
• gpt-5.4-mini
• gpt-5.3-codex
• gpt-5.2
• gpt-5.2-codex
• gpt-5-mini

To switch models, keep the same endpoint, API key, and request format, then change only model.

Troubleshooting

• 401: missing or invalid API key
• 400: invalid Responses API request body, misspelled model id, or unsupported model
• 429: rate limit or temporary capacity limit
• 502 / 504: upstream provider error or timeout

Retry 429, 502, and 504 with backoff. Fix 400 and 401 before retrying.

Related links

• Chat API Overview
• Supported Models
• LLM Authentication
• LLM Streaming
• LLM Errors and Retry
• Install APIXO MCP
• Explore OpenAI models on APIXO
• Pricing

Open a model on APIXO

These links open the selected model on APIXO’s OpenAI gateway page, where you can review its current pricing and copy model-specific code examples.

• GPT-5.5
• GPT-5.4
• GPT-5.4 Mini
• GPT-5.3-Codex
• GPT-5.2
• GPT-5.2-Codex
• GPT-5 Mini