GPT-5.3 Codex API
OpenAI
GPT-5.3 Codex
About GPT-5.3 Codex
GPT-5.3 Codex is a large language model developed by OpenAI. It's particularly well-suited for analyzing images, screenshots, and visual content, tackling complex, multi-step reasoning problems, orchestrating tool-using agents that call APIs and external services, producing structured outputs for reliable data extraction, and handling large contexts of up to 400K tokens. Its 400K-token context window means you can pass in entire documents, codebases, or conversation histories without losing context. Developers choose GPT-5.3 Codex when they need reliable, production-quality AI inference through a simple API — and on Qubax, it's available at a fraction of the cost of traditional providers.
In the broader AI landscape, GPT-5.3 Codex sits among the frontier-tier offerings from OpenAI With advanced reasoning and multimodal vision and agentic tool use, it competes with the most frontier-tier models on the market. What sets it apart on Qubax isn't just the model itself — it's the accessibility. Rather than dealing with enterprise contracts or traditional payment rails, you get instant access via an OpenAI-compatible endpoint. That means you can drop GPT-5.3 Codex into Cursor, Cline, LangChain, or any framework that speaks the OpenAI protocol and start building immediately.
Qubax offers GPT-5.3 Codex at 68% below OpenRouter's price — just $0.569 per million input tokens and $4.55 per million output tokens. That pricing advantage compounds quickly at scale: a high-volume application sending millions of tokens per day can save significantly compared to using OpenRouter or the provider directly. And because Qubax runs on crypto-native infrastructure, you can pay with USDC, USDT, ETH, BTC, or 200+ other cryptocurrencies — no credit card or bank account required. New users even get $1 in free credits to test GPT-5.3 Codex risk-free before committing.
Pricing
| Token Type | Qubax | OpenRouter | You Save |
|---|---|---|---|
| Input (per 1M tokens) | $0.569 | $1.75 | 68% |
| Output (per 1M tokens) | $4.55 | $14.00 | 68% |
Prices per 1 million tokens. Pay with 200+ cryptocurrencies.
Estimated Monthly Cost
Specifications
Use Cases
Capabilities
Quick Start
from openai import OpenAI
client = OpenAI(
base_url="https://api.qubax.ai/v1",
api_key="qbx_live_YOUR_API_KEY",
)
response = client.chat.completions.create(
model="gpt-5.3-codex",
messages=[
{"role": "user", "content": "Hello!"}
],
)
print(response.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.qubax.ai/v1",
apiKey: "qbx_live_YOUR_API_KEY",
});
const response = await client.chat.completions.create({
model: "gpt-5.3-codex",
messages: [{ role: "user", content: "Hello!" }],
});
console.log(response.choices[0].message.content);curl https://api.qubax.ai/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer qbx_live_YOUR_API_KEY" \
-d '{
"model": "gpt-5.3-codex",
"messages": [{"role": "user", "content": "Hello!"}]
}'Get your API key from the dashboard. New users get $1 free credits.
Why use GPT-5.3 Codex on Qubax?
68% Cheaper
Up to 68% off OpenRouter prices
Pay with Crypto
200+ coins (BTC, ETH, SOL, USDT, USDC & more). No credit card needed.
OpenAI Compatible
Drop-in replacement. Works with Cline, Cursor, any tool.
More from OpenAI
Compare GPT-5.3 Codex with alternatives
| Model | Provider | Input / 1M | Output / 1M | vs GPT-5.3 Codex |
|---|---|---|---|---|
| GPT-5.3 Codex | OpenAI | $0.569 | $4.55 | — |
| Hermes 3 Llama 3.1 405b (Morpheus Web) | Meta | $0.572 | $1.56 | More expensive |
| MiniMax M2.1 | MiniMax | $0.291 | $1.16 | Cheaper |
| Kimi K3 | Moonshot AI | $0.520 | $0.494 | Cheaper |
| Qwen 3 Coder 480B Turbo | Alibaba | $0.340 | $1.46 | Cheaper |
Frequently Asked Questions
How much does the GPT-5.3 Codex API cost?
On Qubax, GPT-5.3 Codex costs $0.569 per 1M input tokens and $4.55 per 1M output tokens. This is 68% cheaper than OpenRouter's price of $1.75 per 1M input tokens.
Is the GPT-5.3 Codex API compatible with OpenAI?
Yes. Qubax provides an OpenAI-compatible API. You can use GPT-5.3 Codex as a drop-in replacement by changing your base URL to https://api.qubax.ai/v1 and using your Qubax API key. It works with Cline, Cursor, OpenCode, Hermes Agent, and any tool that supports OpenAI APIs.
Why is GPT-5.3 Codex cheaper on Qubax than OpenRouter?
Qubax sources AI inference from the Surplus Intelligence marketplace, an open marketplace on the Base blockchain where compute providers compete on price. We pass the savings to you — 68% cheaper than OpenRouter's price for GPT-5.3 Codex.
How do I pay for GPT-5.3 Codex API usage?
Qubax uses prepaid crypto credits. Deposit USDC on the Base chain and your balance is automatically deducted as you use the API. New users get $1 in free credits to start. No credit card required.
What is the context window of GPT-5.3 Codex?
GPT-5.3 Codex supports a context window of 400K tokens, allowing you to process large documents, codebases, or long conversations in a single request.
What can I build with GPT-5.3 Codex?
GPT-5.3 Codex is versatile enough for a wide range of applications. You can use it to analyze images and visual content, tackle complex multi-step reasoning tasks, build autonomous agents that call external tools and APIs, generate structured JSON output for data pipelines, process long documents and entire codebases, and more. Because it's served through Qubax's OpenAI-compatible API, integration into existing apps, agents, or workflows takes just a few lines of code.
How fast is GPT-5.3 Codex on Qubax?
GPT-5.3 Codex on Qubax supports streaming responses, so tokens begin arriving in real time as they're generated. Latency depends on the provider and prompt complexity, but most requests start streaming within 200–800 milliseconds. Qubax routes requests through the Surplus Intelligence marketplace, which selects the fastest available compute provider for each request — so you get competitive latency at a lower price.
GPT-5.3 Codex vs Hermes 3 Llama 3.1 405b (Morpheus Web): which should I choose?
GPT-5.3 Codex by OpenAI and Hermes 3 Llama 3.1 405b (Morpheus Web) by Meta are both strong models in a similar price tier. GPT-5.3 Codex excels at complex reasoning and supports vision/image inputs. Hermes 3 Llama 3.1 405b (Morpheus Web) comes from a different lab and may have different strengths depending on your workload. On Qubax, GPT-5.3 Codex starts at $0.569/1M input tokens versus Hermes 3 Llama 3.1 405b (Morpheus Web)'s $0.572/1M — making GPT-5.3 Codex the more cost-effective option for high-volume workloads. Both are available on Qubax with crypto payments and OpenAI-compatible APIs, so you can try each and switch freely.
Can I use GPT-5.3 Codex for commercial projects?
Yes. GPT-5.3 Codex on Qubax can be used for commercial purposes. You own the outputs you generate. Qubax provides the API infrastructure — you bring your use case.
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