What are the strengths of this model?

Advanced coding capabilities Optimized by OpenAI Efficient code generation

What are the weaknesses of this model?

Is closed-source Potential usage restrictions Internal architecture is not public

What are the best use cases?

Automatic generation of source code Fixing program bugs Improving development workflow efficiency

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OpenAIProprietary

OpenAI GPT-5.1 Codex Mini

Name: OpenAI GPT-5.1 Codex Mini
Author: OpenAI

OpenAI GPT-5.1 Codex Mini, developed by OpenAI, is a foundation model specialized in programming. It is designed to enhance code generation and development efficiency.

Parameters

Undisclosed

Context Window

License

Proprietary

Release Date

2025-11-14

API Pricing

API pricing for this model is not yet available

Strengths

・Advanced coding capabilities
・Optimized by OpenAI
・Efficient code generation

Weaknesses

・Is closed-source
・Potential usage restrictions
・Internal architecture is not public

Use Cases

・Automatic generation of source code
・Fixing program bugs
・Improving development workflow efficiency

Deep Analysis

Release Date

November 12-13, 2025

Context Window

400K tokens

Max Output

128K tokens

Input Price

$0.25 / 1M tokens

Output Price

$2.00 / 1M tokens

Modality

Text, Images, Audio, Video input

Design Focus

Steerability, front-end development, interactivity

License

Proprietary, Closed-source

Strengths

・Extremely cost-effective at $0.25/$2.00 per 1M tokens — 5x cheaper than GPT-5.1 Codex
・Large 400K context window despite being a 'mini' model
・Designed for steerability and front-end development workflows
・Supports multimodal input (text, images, audio, video)
・Good for high-volume coding tasks where cost is the primary concern

Weaknesses

・Lower coding accuracy than full GPT-5.1 Codex (SWE-bench 73.7% for Codex, no published score for Mini)
・No published benchmark scores for direct comparison
・Not suitable for complex multi-file architecture changes
・Lacks the deep reasoning of the full Codex or Codex-Max variants
・Limited to 'mini' quality — may struggle with subtle or complex code patterns

Competitor Comparison

Model	Arena	SWE	GPQA	Price
Claude Haiku 4	~1350	~45%	~72%	$0.25/$1.25 per 1M tokens
Gemini 3 Flash	~1370	~50%	~78%	$0.15/$0.60 per 1M tokens
GPT-5.1 Codex	~1400	73.7%	~88%	$1.25/$10 per 1M tokens
GPT-5 mini	~1340	~40%	~70%	$0.25/$2.00 per 1M tokens

Overview

GPT-5.1 Codex Mini is OpenAI's cost-efficient coding model released November 12-13, 2025, designed for steerability, front-end development, and interactive coding workflows. At $0.25/$2.00 per 1M tokens with a 400K context window, it offers the best value for high-volume coding tasks. It is 5x cheaper than the full GPT-5.1 Codex while sharing the same context window capacity.

Benchmarks & Performance

GPT-5.1 Codex Mini does not have published SWE-bench or Terminal-Bench scores. The AIME 2025 score of 42.1% is the only published benchmark. It is designed for steerability and front-end development rather than deep reasoning. The model supports multimodal inputs (text, images, audio, video) and is optimized for interactive coding workflows. Its quality level is expected to be below GPT-5.1 Codex (SWE-bench 73.7%) but above GPT-5 mini.

Detailed Comparison

GPT-5.1 Codex Mini is 5x cheaper than GPT-5.1 Codex ($0.25/$2 vs $1.25/$10) with the same 400K context window, but trades coding accuracy for cost. It competes with Claude Haiku 4 ($0.25/$1.25) and Gemini 3 Flash ($0.15/$0.60) on price. Compared to GPT-5 mini ($0.25/$2), it offers coding specialization at the same price. For production coding tasks, GPT-5.1 Codex or Codex-Max provide significantly better accuracy.

Community Feedback

The model is valued for front-end development and interactive coding tasks where speed and cost matter more than accuracy. Developers appreciate the large context window at mini-tier pricing. The main complaint is the lack of published benchmarks, making it hard to evaluate against alternatives. It is popular for rapid prototyping, boilerplate generation, and code scaffolding but not trusted for critical production code.

Use Cases

Best for: front-end development and UI scaffolding, rapid prototyping, boilerplate code generation, high-volume code review triage, interactive coding sessions, code style enforcement, and localized bugfixes. NOT suitable for: complex multi-file refactoring, security-critical code, algorithm design, long-horizon autonomous coding, or tasks requiring maximum accuracy. Use GPT-5.1 Codex or Codex-Max for production-grade work.

Latest News

Released November 12-13, 2025 alongside the GPT-5.1 family. Available on Azure (gpt-5.1-codex-mini, version 2025-11-13) and OpenAI API. Microsoft describes it as 'designed for steerability, front end development, and interactivity.'

Sources

Analysis generated: 2026-05-24