# GPT-5.1 Codex ![Organization](https://img.shields.io/badge/Org-OpenAI-74aa9c) ![License](https://img.shields.io/badge/License-Proprietary-d29922) ![Released](https://img.shields.io/badge/Released-Feb%202026-555) ![Focus](https://img.shields.io/badge/Focus-Coding-1f6feb) > **Quick answer:** GPT-5.1 Codex is OpenAI's February 2026 coding-specialised model, scoring 73.7% on SWE-Bench Verified. It is the updated successor to GPT-5 Codex with a more recent September 2025 knowledge cutoff. ## At a Glance **Where GPT-5.1 Codex leads** - 73.7% SWE-Bench Verified — strong software engineering - More recent knowledge cutoff (September 2025) vs GPT-5 Codex (September 2024) - Latest Codex generation from OpenAI **Where it lags** - Slightly below GPT-5 Codex on SWE-Bench (73.7% vs 74.5%) - Below DeepSeek-V4 Flash Max (79%) on SWE-Bench - Proprietary: no open weights **Best for:** Current-generation coding tasks via the OpenAI API; SWE-Bench class software engineering; automated coding agents. ## What GPT-5.1 Codex Is GPT-5.1 Codex (released February 2026) is OpenAI's updated Codex model — the February 2026 iteration of the coding-specialised GPT-5 Codex family. The ".1" suffix indicates an incremental update, with a significantly more recent knowledge cutoff (September 2025 vs September 2024). The model's 73.7% SWE-Bench Verified score is marginally below GPT-5 Codex (74.5%), suggesting evaluation methodology or benchmark drift rather than capability regression. Both models are competitive in the 73-75% SWE-Bench range. ## Specifications | Field | Value | |---|---| | Organization | OpenAI | | License | Proprietary (API only) | | Release date | February 2026 | | Knowledge cutoff | September 2025 | | Modality | Text / Code | ## Pricing Available via OpenAI API — refer to the OpenAI pricing page. ## Public Benchmark Scores | Benchmark | Score | Source | Date | |---|---|---|---| | [SWE-Bench Verified](/benchmarks/swe-bench-verified) | 73.7% | Benchgen evaluation | 2026-02 | ## GPT-5.1 Codex vs Alternatives | Model | SWE-Bench Verified | Knowledge Cutoff | |---|---|---| | **GPT-5.1 Codex** | 73.7% | Sep 2025 | | [GPT-5 Codex](/models/openai/gpt-5-codex) | 74.5% | Sep 2024 | | [DeepSeek-V4 Flash Max](/models/deepseek/deepseek-v4-flash-max) | 79% | Sep 2025 | GPT-5.1 Codex is preferred over GPT-5 Codex for current-date code knowledge (Sep 2025 cutoff). For maximum SWE-Bench: DeepSeek-V4 Flash Max (79%, proprietary). ## Related Models & Benchmarks - Compare: [GPT-5 Codex](/models/openai/gpt-5-codex) · [DeepSeek-V3.2 Speciale](/models/deepseek/deepseek-v3-2-speciale) · [DeepSeek-V4 Flash Max](/models/deepseek/deepseek-v4-flash-max) - Benchmarks: [SWE-Bench Verified](/benchmarks/swe-bench-verified) ## Frequently Asked Questions

What is GPT-5.1 Codex?

OpenAI's February 2026 updated coding model scoring 73.7% SWE-Bench Verified with a September 2025 knowledge cutoff.

Should I use GPT-5 Codex or GPT-5.1 Codex?

GPT-5.1 Codex for most uses — more recent knowledge cutoff (Sep 2025 vs Sep 2024). GPT-5 Codex has marginally higher SWE-Bench (74.5% vs 73.7%).

--- *Specs from OpenAI's GPT-5.1 Codex release (February 2026) and Benchgen evaluations. Last updated 2026-07-24.*

GPT-5.1 Codex — Files