Question 1

What is GPT-5.1-Codex?

Accepted Answer

Information about What is GPT-5.1-Codex for OpenAI: GPT-5.1-Codex.

Question 2

What is OpenAI Codex used for?

Accepted Answer

Information about What is OpenAI Codex used for for OpenAI: GPT-5.1-Codex.

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

What is the difference between GPT-5.1 and GPT-5.1-Codex Max?

Accepted Answer

Starting today, GPT‑5.1-Codex-Max will replace GPT‑5.1-Codex as the default model in Codex surfaces. Unlike GPT‑5.1, which is a general-purpose model, we recommend using GPT‑5.1-Codex-Max and the Codex family of models only for agentic coding tasks in Codex or Codex-like environments.

Question 5

Is GPT-5.1 Codex good?

Accepted Answer

Bottom Line. GPT-5.1 Codex is really, really good. It delivers integrated code that handles edge cases, costs 43% less than Claude, and needs minimal polish. GPT-5 was already solid, but GPT-5.1's improvements in speed and architecture make it the clear choice for new work.

OpenAI: GPT-5.1-Codex

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