Question 1

What is GPT-5 Codex?

Accepted Answer

Information about What is GPT-5 Codex for OpenAI: GPT-5 Codex.

Question 2

What is GPT-5.1 Codex?

Accepted Answer

What is GPT-5.1-Codex? GPT-5.1 Codex is a specialized version of GPT-5.1, built for long-running, agentic coding tasks rather than just snippet autocompletion. It is purpose-built for real software engineering and agentic workflows, which makes it the perfect engine behind our Issue-to-Plan automation workflow.

Question 3

What is the difference between OpenAI Codex and GPT?

Accepted Answer

Both models use similar APIs, but Codex's outputs are constrained to code structures, while GPT's outputs prioritize natural language coherence. Use cases also differ significantly. Codex is ideal for code autocompletion, translating pseudocode to executable programs, or documenting existing code.

Question 4

Is Codex OpenAI free?

Accepted Answer

Information about Is Codex OpenAI free for OpenAI: GPT-5 Codex.

Question 5

What is the difference between GPT-5 and GPT-5 Codex?

Accepted Answer

GPT‑5-Codex was purpose-built for Codex CLI, the Codex IDE extension, the Codex cloud environment, and working in GitHub, and also supports versatile tool use. Unlike GPT‑5, which is a general-purpose model, we recommend using GPT‑5-Codex only for agentic coding tasks in Codex or Codex-like environments.

OpenAI: GPT-5 Codex

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