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The most capable agentic coding model ever built, combining frontier coding, deep reasoning, and full computer-use into one model that works with you, not just for you.
Meet GPT‑5.3 Codex, OpenAI’s most advanced agentic coding model for building autonomous, tool‑using developer agents and production‑grade AI workflows. Unlike a simple code autocomplete tool, GPT‑5.3‑Codex can initiate and sustain long-running tasks: conducting research, using external tools, managing deployments, writing documentation, and iterating on complex software over millions of tokens — all while keeping you actively in the loop.
Achieves state-of-the-art performance on SWE-Bench Pro — a rigorous, multi-language real-world software engineering benchmark. Resolves complex GitHub issues across Python, JavaScript, TypeScript, Rust, and more.
Builds fully functional, visually polished web apps and games from scratch. GPT‑5.3‑Codex autonomously iterated on complex games over millions of tokens, understanding intent without exhaustive specification.
Reads documentation, runs web research, analyzes structured data, and writes comprehensive reports. It can summarize thousands of data points in minutes with concise, actionable insights.
Matches GPT‑5.2 on GDPval — OpenAI's benchmark across 44 occupations. Creates presentations, spreadsheets, PRDs, financial analyses, training documents, and more at professional quality.
GPT‑5.3‑Codex achieves new state-of-the-art results on four benchmarks measuring coding ability, terminal proficiency, computer use, and professional knowledge work.

GPT‑5.3 Codex is best suited where coding, tool‑use, and structured reasoning must come together.
Meet GPT‑5.3 Codex, OpenAI’s most advanced agentic coding model for building autonomous, tool‑using developer agents and production‑grade AI workflows. Unlike a simple code autocomplete tool, GPT‑5.3‑Codex can initiate and sustain long-running tasks: conducting research, using external tools, managing deployments, writing documentation, and iterating on complex software over millions of tokens — all while keeping you actively in the loop.
Achieves state-of-the-art performance on SWE-Bench Pro — a rigorous, multi-language real-world software engineering benchmark. Resolves complex GitHub issues across Python, JavaScript, TypeScript, Rust, and more.
Builds fully functional, visually polished web apps and games from scratch. GPT‑5.3‑Codex autonomously iterated on complex games over millions of tokens, understanding intent without exhaustive specification.
Reads documentation, runs web research, analyzes structured data, and writes comprehensive reports. It can summarize thousands of data points in minutes with concise, actionable insights.
Matches GPT‑5.2 on GDPval — OpenAI's benchmark across 44 occupations. Creates presentations, spreadsheets, PRDs, financial analyses, training documents, and more at professional quality.
GPT‑5.3‑Codex achieves new state-of-the-art results on four benchmarks measuring coding ability, terminal proficiency, computer use, and professional knowledge work.

GPT‑5.3 Codex is best suited where coding, tool‑use, and structured reasoning must come together.