GPT-5.3-Codex
GPT-5.3-Codex sits in the frontier tier, built for high-capability reasoning, tool use, and long-form output where capability outweighs cost. Available via OpenAI. 400,000-token context. Premium pricing.
GPT-5.3-Codex is a multimodal AI model from OpenAI. It costs $1.750 per million input tokens and $14.000 per million output tokens (blended $5.425/M), with a 400,000-token context window.
- Strong general reasoning
- Tool use & function calling
- Long-form writing
- Production-grade reliability
- Multimodal: handles images alongside text
- Production assistants
- Long-document analysis
- Multi-step agent workflows
- Engineering copilots
Benchmarks
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How much does GPT-5.3-Codex cost?
GPT-5.3-Codex costs $1.750 per million input tokens and $14.000 per million output tokens, for a blended reference rate of $5.425 per million tokens.
What is GPT-5.3-Codex's context window?
GPT-5.3-Codex supports up to 400,000 tokens of context in a single request.
What is GPT-5.3-Codex best for?
GPT-5.3-Codex is well suited to Strong general reasoning, Tool use & function calling and Long-form writing.
Who makes GPT-5.3-Codex?
GPT-5.3-Codex is developed and served by OpenAI.