GPT 5.3 Codex
OpenAI
GPT-5.3-Codex advances both the frontier coding performance of GPT‑5.2-Codex and the reasoning and professional knowledge capabilities of GPT‑5.2, together in one model, which is also 25% faster. This enables it to take on long-running tasks that involve research, tool use, and complex execution.
- Language
- File input
- Implicit caching
- Reasoning
- Tool use
- Vision
- Web search
- Realtime socket
- Fast
- Context
- 400K
- Max output
- 128K
- Input / 1M
- $1.75
- Output / 1M
- $14.00
Quickstart
Point any OpenAI-compatible client at Maxynetic Systems and pass openai/gpt-5.3-codex as the model.
curl https://api.maxynetic.com/v1/chat/completions \
-H "Authorization: Bearer $MAXYNETIC_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-5.3-codex",
"messages": [{ "role": "user", "content": "Explain routing in one line." }]
}'Pricing
Billed per token with no markup on the underlying provider rate.
Input
Per 1M prompt tokens
$1.75
Output
Per 1M completion tokens
$14.00
Cache read
Per 1M cached prompt tokens
$0.175
A 1M-token prompt with 250K tokens of output costs about $5.25.