GPT-5-Codex
GPT-5-Codex is an API-only (closed weights) language model from OpenAI, released September 15, 2025.
Today, we’re releasing GPT‑5-Codex—a version of GPT‑5 further optimized for agentic coding in Codex. GPT‑5-Codex was trained with a focus on real-world software engineering work; it’s equally proficient at quick, interactive sessions and at independently powering through long, complex tasks.
Check it against your own PC →
Lab
OpenAI
Released
September 15, 2025
Weights
API-only (closed weights)
Parameters
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Context
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Price / M tokens
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Epoch ECI
not yet rated
Benchmark results
Epoch AI has not published results for GPT-5-Codex yet. New models are usually evaluated within days to weeks.
Links
More from OpenAI
GPT-6.1 Terra · GPT-6.1 Sol · GPT-6 Sol · GPT-6 Luna · GPT-6 Astra · GPT-5.6 Cyber · Daybreak Red · Daybreak Blue