OpenAIReleased on Nov 19, 2025

GPT-5.1 Codex: API Pricing, Context Window & Benchmarks

GPT-5.1 Codex is a language model from OpenAI, released in November 2025, with multimodal input.

GPT-5.1 Codex is a version of GPT-5.1 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.

Input
TextImage
Output
Text
Speed
Latency p953.00s
Throughput P9550.0char/s
Cost
$2.22/ 1M · 8:1 in:out
$1.25 in · $10.0 out

GPT-5.1 Codex benchmarks

Rankings

Quality Tracker

GPT-5.1 Codex Performance Across Datasets

Scores sourced from the model's scorecard, paper, or official blog posts

LLM Stats Logollm-stats.com - Sat Jul 25 2026
Notice missing or incorrect data?

GPT-5.1 Codex pricing

Providers

GPT-5.1 Codex starts at $1.25 per million input tokens and $10.00 per million output tokens via OpenAI.

ProviderInput $/MOutput $/MContext in / outTTFT p50 / p95 sOutput avg / p5 c/sSuccess 7dModalities in / out
OpenAI logoOpenAI
$1.25$10.00400.0K/128.0K
—/3.00
50/—
—
/

Cached input is the discounted price for prompt tokens served from a provider cache. TTFT is time to first token. Output is characters per second; p5 is the sustained floor exceeded by 95% of observed requests. Success is calculated from completed versus failed requests over the trailing seven days.

GPT-5.1 Codex context window

Input and output token limits for GPT-5.1 Codex, plus how it ranks on long-context understanding.

InputOutput
400Ktokens
128Ktokens
≈ 602 pages of text
400K
8K128K1M

GPT-5.1 Codex API

Available from the model provider

GPT-5.1 Codex has an official provider API. It is not currently routed through the LLM Stats gateway.

Read the official API documentation

GPT-5.1 Codex latency

GPT-5.1 Codex time to first token, sustained output throughput, and failed-request rate from live API traffic over the trailing 7 days.

GPT-5.1 Codex examples

Recent arena outputs from GPT-5.1 Codex, picked from the highest-ranked matchups.

GPT-5.1 Codex license

GPT-5.1 Codex is a proprietary model available under its provider's product and API terms, has a knowledge cutoff of September 2024.

License
Proprietary
Hosted access
Knowledge cutoff
September 2024

Proprietary license - usage restrictions apply

GPT-5.1 Codex resources

Official sources for GPT-5.1 Codex: api documentation, paper or system card, official launch post.

GPT-5.1 Codex vs other models

The most-compared alternatives to GPT-5.1 Codex are Gemini 3 Pro, Seed 2.0 Lite, Step-3.5-Flash. Open any pair side-by-side for benchmarks, pricing, context, and latency.

Models like GPT-5.1 Codex

Models ranked just above and below GPT-5.1 Codex by LLM Stats score.

 

Gemini 3 Pro

Score pending
DetailsCompare
 

Seed 2.0 Lite

Score pending
DetailsCompare
 

Step-3.5-Flash

Score pending
DetailsCompare
 

MAI-Thinking-1

Score pending
DetailsCompare
 

Qwen3.5-397B-A17B

Score pending
DetailsCompare
 

GLM-4.7

Score pending
DetailsCompare

FAQ

Common questions about GPT-5.1 Codex.

When was GPT-5.1 Codex released?

GPT-5.1 Codex was released on November 19, 2025 by OpenAI. This is the official GPT-5.1 Codex release date tracked on LLM Stats.

How much does GPT-5.1 Codex cost?

GPT-5.1 Codex pricing starts at $1.25 per million input tokens and $10.00 per million output tokens via OpenAI, the lowest price among tracked providers.

Is GPT-5.1 Codex available via API?

Yes, GPT-5.1 Codex is available via API. See the official documentation for authentication and endpoint details. It is served by 1 provider tracked on LLM Stats.

Who created GPT-5.1 Codex?

GPT-5.1 Codex was created by OpenAI.

What is the license for GPT-5.1 Codex?

GPT-5.1 Codex is released under the Proprietary license.

What is the knowledge cutoff date for GPT-5.1 Codex?

GPT-5.1 Codex has a knowledge cutoff of September 2024, meaning it was trained on data up to that point and may not know about events after it.

Is GPT-5.1 Codex multimodal?

Yes, GPT-5.1 Codex is multimodal and can accept both text and images as input.

What is GPT-5.1 Codex latency?

GPT-5.1 Codex p95 time to first token is 3.00 seconds via OpenAI over the trailing 7 days. Lower time to first token means the model begins responding sooner for chat, agents and API workloads.

Where can I use GPT-5.1 Codex?

GPT-5.1 Codex is available through 1 provider including OpenAI.

Where is the GPT-5.1 Codex paper or technical report?

GPT-5.1 Codex has a paper or technical report available at https://cdn.openai.com/pdf/2a7d98b1-57e5-4147-8d0e-683894d782ae/5p1_codex_max_card_03.pdf. Use that source for architecture, training, release and evaluation details.

What models should I compare GPT-5.1 Codex against?

Common GPT-5.1 Codex comparisons include GPT-5.1 Codex vs Gemini 3 Pro, GPT-5.1 Codex vs Seed 2.0 Lite, GPT-5.1 Codex vs Step-3.5-Flash. Compare them side by side for benchmark scores, pricing, context window, latency and API availability.