GPT-5.3-Codex

Available

OpenAIProprietary

OpenAI's February 2026 Codex update, optimized for agentic software engineering in ChatGPT, Codex, and the API. GPT-5.3-Codex improves code quality, patch reliability, repository-scale reasoning, and long-running autonomous coding workflows while keeping the 400K-token input context and 128K-token output limit of the Codex line.

Official page ↗Model card ↗

Specifications

License: Proprietary
Weights: Not released
Architecture: unknown
Parameters: Undisclosed
Context window: 400K tokens
Max output: 128K tokens
Knowledge cutoff: —
Price (in / out, $/M): $1.25 / $10
Modalities: TextVisionCode

Benchmarks

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Vendor-reported figures are claims until independently verified. See methodology.