OpenAI: GPT-5.3-Codex · fastrouter
GPT-5.3-Codex is OpenAI's most capable agentic coding model to date, combining frontier coding performance with general work automation capabilities—enabling developers and professionals to automate complex tasks across the entire software lifecycle, from code writing to infrastructure management and cybersecurity.
Input, $/1M $1.75
Output, $/1M $14.00
Cache read $0.17
Cache write —
Context 400 000
Max output 128 000
Accepts images, text
Last checked 04.11.2026 12:00:14 UTC
Source provider's page
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API
OpenAI-compatible API: the official OpenAI SDKs work with this base URL. Replace YOUR_API_KEY with your key from the provider.
| API base URL | |
|---|---|
| Endpoint | |
| Model id | |
curl
curl https://go.fastrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "openai/gpt-5.3-codex", "messages": [{"role": "user", "content": "Hello!"}], "max_tokens": 256}'Python
import requests
r = requests.post(
"https://go.fastrouter.ai/api/v1/chat/completions",
headers={"Authorization": "Bearer YOUR_API_KEY"},
json={
"model": "openai/gpt-5.3-codex",
"messages": [
{
"role": "user",
"content": "Hello!"
}
],
"max_tokens": 256
},
)
print(r.json())JavaScript
const r = await fetch("https://go.fastrouter.ai/api/v1/chat/completions", {
method: "POST",
headers: {Authorization: "Bearer YOUR_API_KEY", "Content-Type": "application/json"},
body: JSON.stringify({
"model": "openai/gpt-5.3-codex",
"messages": [
{
"role": "user",
"content": "Hello!"
}
],
"max_tokens": 256
}),
});
console.log(await r.json());Request (JSON)
{
"model": "openai/gpt-5.3-codex",
"messages": [
{
"role": "user",
"content": "Hello!"
}
],
"max_tokens": 256
}Response (JSON)
{
"id": "chatcmpl-...",
"object": "chat.completion",
"model": "openai/gpt-5.3-codex",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "Hi! How can I help?"
},
"finish_reason": "stop"
}
],
"usage": {
"prompt_tokens": 9,
"completion_tokens": 12,
"total_tokens": 21
}
}The address is taken from the provider's model list; check it against the provider's documentation.
Source: AI Rate Card, https://airatecard.com/en/c/offer%3Afastrouter%7Copenai/gpt-5.3-codex, prices checked 2026-11-04; seller's page: https://fastrouter.ai/models/openai/gpt-5.3-codex
Technical details
ID: offer:fastrouter|openai/gpt-5.3-codex