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OpenAI model product

GPT-5.1-Codex

1 optimized for agentic coding tasks in Codex or similar environments.

Updated Aug 12, 2026. Default version: GPT-5.1 Codex

Compare
LLMBoard score49.5GPT-5.1 Codex
Coverage20%3 benchmark families
Context window400KTokens
Official input priceN/AOfficial price unavailable

On this page

  • Specification
  • Capability
  • Benchmarks
  • Arena
  • Runtime
  • Pricing
  • Versions
  • About
  • Compare
  • Similar models
  • FAQ

GPT-5.1-Codex Specifications

Technical details for the model's default version.

Version
GPT-5.1 Codex
Released
Nov 19, 2025
Knowledge cutoff
Sep 30, 2024
Parameters
N/A
Context window
400K
Max output
128K
Inputs
image, text
Outputs
text
Open weights
No
License
Proprietary

GPT-5.1-Codex Capability Profile

This profile uses the model's current scored version. Arena ratings and prices are shown separately.

GPT-5.1 Codex category scores

GPT-5.1-Codex Benchmark Results

Benchmark scores for GPT-5.1 Codex.

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SWE-Lancer66.3%014100.0%CAug 11, 2026
Terminal-Bench 2.052.8%314937.5%CAug 11, 2026
SWE-Bench Verified73.7%4110561.5%CAug 11, 2026

GPT-5.1-Codex Arena Results

Preference and agent-evaluation results for the default version.

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webdevoverall851335.94,873N/AAug 10, 2026

GPT-5.1-Codex Runtime Performance

Provider-specific output speed and catalog latency for GPT-5.1 Codex. Runtime does not affect the capability score.

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OpenAI50 tok/s3 s400K128KAug 11, 2026

Output Speed is generated output tokens received per second. Catalog latency is reported separately from observed provider TTFT.

GPT-5.1-Codex Pricing

Official vendor API pricing appears first, followed by individual provider offers.

Official API
N/A
Official provider
N/A
Lowest third-party
From $1.07 input, $8.5 output per 1M via OpenCode Zen
Tracked offerings
18
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OpenCode Zengpt-5.1-codexglobal$1.07$8.5400KAug 11, 2026
Poeopenai/gpt-5.1-codexglobal$1.1$9400KAug 11, 2026
Jiekou.AIgpt-5.1-codexglobal$1.13$9400KAug 11, 2026
Impossiblopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Vivgridgpt-5.1-codexglobal$1.25$10400KAug 11, 2026
NanoGPTopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
LLM Gatewaygpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Heliconegpt-5.1-codexglobal$1.25$10400KAug 11, 2026
ZenMuxopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Abacusgpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Azure Cognitive Servicesgpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Azuregpt-5.1-codexglobal$1.25$10400KAug 11, 2026
AIHubMixgpt-5.1-codexglobal$1.25$10400KAug 11, 2026
OrcaRouteropenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Kilo Gatewayopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Vercel AI Gatewayopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
OpenRouteropenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026
Cloudflare AI Gatewayopenai/gpt-5.1-codexglobal$1.25$10400KAug 11, 2026

Official prices use only the vendor's configured official Provider and positive standard USD PAYG rates. Third-party offers remain explicitly labeled.

GPT-5.1-Codex Versions

Available versions of this model. The score column identifies the version used in the overall ranking.

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GPT-5.1 CodexNov 19, 202549.5N/A400K128KNoProprietary
GPT-5.1 Codex HighNov 12, 2025N/AN/A400K128KNoProprietary

What is GPT-5.1-Codex?

Key information about GPT-5.1-Codex and its available data.

1 optimized for agentic coding tasks in Codex or similar environments. It features higher reasoning capabilities and is available in the Responses API. The underlying model snapshot is regularly updated.

Data as of 2026-08-11.

GPT-5.1-Codex vs nearby models

Open a comparison with the three ranked models immediately above and below this model.

GPT-5.1-CodexvsMAI Code 1 FlashGPT-5.1-CodexvsGemini 2.5 ProGPT-5.1-CodexvsGPT-5GPT-5.1-CodexvsGLM 4.5GPT-5.1-CodexvsMistral Medium 3.5GPT-5.1-CodexvsGPT-5.4-nano

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FAQ

Common questions about GPT-5.1-Codex.

When was GPT-5.1-Codex released?

GPT-5.1-Codex's default version was released on Nov 19, 2025.

How much does GPT-5.1-Codex cost?

No official standard PAYG price is currently available for GPT-5.1-Codex. The lowest tracked third-party offer starts at $1.07 input and $8.5 output via OpenCode Zen.

Who created GPT-5.1-Codex?

GPT-5.1-Codex was created by OpenAI.

What is the context window for GPT-5.1-Codex?

The default version has a 400K token context window.

Is GPT-5.1-Codex open weight?

No. The default version is not marked as having publicly available weights.

How many API providers offer GPT-5.1-Codex?

18 provider offerings are linked to the default version.

What models should I compare GPT-5.1-Codex with?

Nearby ranked alternatives include MAI Code 1 Flash, Gemini 2.5 Pro, GPT-5.