OpenAI Coding Big Closed weights

GPT-5.3-Codex

280 days since OpenAI announced it · 5 Feb 2026

GPT-5.3-Codex is a closed-weights coding model from OpenAI, announced 5 Feb 2026. It costs $1.75 per 1M input tokens and $14 per 1M output tokens. Its context window is 400K tokens.

Input: $1.75; per 1M tokens
Cache write: —; per 1M tokens
Cache read: —; per 1M tokens
Output: $14; per 1M tokens
Context window: 400K; tokens
Parameters: —; not disclosed

Announcement: openai.com/index/introducing-gpt-5-3-codex
Docs: developers.openai.com/api/docs/models/gpt-5.3-codex

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OpenAI · Big · Codex

closed weights

GPT-5.3-Codex +49d 5 Feb 2026
GPT-5.2-Codex +29d 18 Dec 2025
GPT-5.1-Codex-Max 19 Nov 2025