87% offGPT-5.3 Codex API
OpenAI·Text· 100.0% success (7d)
GPT-5.3 Codex
Pricing
Cheapest live price, per 1 million tokens.
Input / 1M tokens
$1.75 OpenRouter
Output / 1M tokens
$14.00 OpenRouter
Cache read / 1M
Repeated prompt prefixes
Cache read is the discounted rate for repeated prompt prefixes (system prompts, agent context).
Capabilities · 12
Specifications
- Context window
- 400K
- Max output
- 128K
- Type
- Text
- Creator
- OpenAI
- Live sellers
- 106
- Requests / 24h
- 1,062
Price history · 60 days
Estimated monthly cost
30 days at the cheapest live price.
Quick start
OpenAI-compatible — change the base URL and key. Get a key from the dashboard.
from openai import OpenAI
client = OpenAI(
base_url="https://api.qubax.ai/v1",
api_key="YOUR_QUBAX_API_KEY",
)
response = client.chat.completions.create(
model="gpt-5.3-codex",
messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)About GPT-5.3 Codex
GPT-5.3 Codex is a 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. It can write up to 128K tokens in a single response.
As of Nov 4, 2026, GPT-5.3 Codex costs $0.440 per 1M input tokens and $1.78 per 1M output tokens on Qubax, versus $1.75 / $14.00 on OpenRouter (75% less on input). A typical 1,000 chat requests (2K tokens in, 500 out) come to about $1.77. Measured availability over the last 7 days: 100.0%. 106 independent compute providers currently serve it, so requests fail over automatically. It handled 1,062 requests on Qubax in the last 24 hours. Pay with USDC, USDT, BTC, ETH or 350+ other coins — no credit card required.
Similar-priced alternatives
Frequently asked questions
How much does the GPT-5.3 Codex API cost?
On Qubax, GPT-5.3 Codex costs $0.440 per 1M input tokens and $1.78 per 1M output tokens. This is 75% 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 an open compute marketplace on the Base blockchain where GPU providers compete on price. We pass the savings to you — 75% 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. Top up with USDC, USDT, BTC, ETH, SOL or 350+ other coins and your balance is deducted as you use the API. No credit card or KYC 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?
You can use GPT-5.3 Codex 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 and process long documents and entire codebases. 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 and reliable is GPT-5.3 Codex on Qubax?
Measured time to first token (p95) on Qubax is 29.6s. Its 7-day success rate is 100.0%. Responses stream token by token. 106 sellers serve it, so if one is slow or down the request moves to the next.
GPT-5.3 Codex vs NVIDIA Nemotron 3 Ultra 550B: which should I choose?
GPT-5.3 Codex by OpenAI and NVIDIA Nemotron 3 Ultra 550B by Other are both strong models in a similar price tier. GPT-5.3 Codex excels at complex reasoning and supports vision/image inputs. NVIDIA Nemotron 3 Ultra 550B comes from a different lab and may have different strengths depending on your workload. On Qubax, GPT-5.3 Codex starts at $0.440/1M input tokens versus NVIDIA Nemotron 3 Ultra 550B's $0.460/1M — 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.
Why use GPT-5.3 Codex on Qubax?
87% cheaper
Providers compete on price — you get the cheapest healthy seller.
Pay with crypto
350+ coins (BTC, ETH, SOL, USDT, USDC). No card, no KYC.
OpenAI & Anthropic compatible
Drop-in base URL. Works with Cline, Cursor, Claude Code, OpenAI and Anthropic SDKs.