free-ai-api-keys

openai/gpt-5.3-codex

OpenAI: GPT-5.3-Codex

Context length
400K
Input / 1M tokens
$1.75
Output / 1M tokens
$14.00
Released
2026-02-24
Modality
text+image+file->text

About OpenAI: GPT-5.3-Codex

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

Call OpenAI: GPT-5.3-Codex

Via OpenRouter: one base URL for every provider.

curl https://openrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.3-codex",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

Direct on OpenAI:

curl https://api.openai.com/v1/chat/completions \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-5.3-codex",
    "messages": [{"role": "user", "content": "Say hello"}]
  }'

OpenAI keys

OpenRouter keys

OpenRouter keys work for openai/gpt-5.3-codex regardless of the upstream provider.