GPT 5.3 Codex
openai/gpt-5.3-codexGPT 5.3 Codex (openai/gpt-5.3-codex) is an AI model from OpenAI with a 272,000-token context window and 128,000 max output tokens, priced at $1.75/1M input and $14.00/1M output tokens. Available via the haimaker.ai OpenAI-compatible API.
Overview
OpenAI's Codex model specialized for code generation, software engineering, and agentic coding tasks.
Features & Capabilities
| Mode | responses |
| Context Window | 272,000 tokens |
| Max Output | 128,000 tokens |
| Function Calling | Supported |
| Vision | Supported |
| Reasoning | Supported |
| Web Search | Supported |
| Url Context | - |
API Usage
from openai import OpenAI
client = OpenAI(
base_url="https://api.haimaker.ai/v1",
api_key="YOUR_API_KEY",
)
response = client.chat.completions.create(
model="openai/gpt-5.3-codex",
messages=[
{"role": "user", "content": "Hello, how are you?"}
],
)
print(response.choices[0].message.content)Frequently Asked Questions
What is the context window of GPT 5.3 Codex?
GPT 5.3 Codex (openai/gpt-5.3-codex) has a 272,000-token context window and supports up to 128,000 output tokens per request.
How much does GPT 5.3 Codex cost?
GPT 5.3 Codex is priced at $1.75 per 1M input tokens and $14.00 per 1M output tokens when accessed via the haimaker.ai OpenAI-compatible API.
What features does GPT 5.3 Codex support?
GPT 5.3 Codex supports function calling, vision, reasoning, web search.
How do I use GPT 5.3 Codex via API?
Send requests to https://api.haimaker.ai/v1/chat/completions with model "openai/gpt-5.3-codex" using any OpenAI-compatible SDK. Authentication uses a Bearer API key from https://app.haimaker.ai.
Use GPT 5.3 Codex with the haimaker API
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