GPT-5.1 Codex Mini

GPT-5.1 Codex Mini API Overview

GPT-5.1 Codex Mini is a lightweight, highly optimized version of OpenAI’s latest GPT-5.1 series, specifically designed for coding workflows and software development assistance. It strikes a balance between performance and resource efficiency, rendering it suitable for integration into environments that demand fast, reliable code generation with minimal latency.

Technical Specifications

• Model Type: Transformer-based language model specialized in code understanding and generation
• Context: 400K
• Training Data: Extensive corpus of programming code, documentation, and software development discussions
• Supported Modalities: Text input, code snippets, optionally interpretable images for UI/UX visual aid

Performance Benchmarks

• Code Completion Accuracy: Achieves over 85% accuracy on popular datasets such as HumanEval and APPS
• Reliability: Maintains high correctness rate in debugging and refactoring tasks
• Multi-Task Efficiency: Performs simultaneous code review, comment generation, and bug fixing with minimal latency

Key Features

• Optimized for Coding Tasks: Tailored for code synthesis, debugging, refactoring, and documentation
• Steerable Behavior: Adjustable reasoning and output coherence with custom parameters
• Multimodal Support: Can interpret images/screenshots for UI development and visual debugging
• Enhanced Steerability: Responds closely to developer instructions for cleaner, precise code outputs

GPT-5.1 API Pricing

• Input: $0.2625 per 1M tokens‍
• Cached Input: $0.02625 per 1M tokens‍
• Output: $2.10 per 1M tokens

Code Sample

Comparison with Other Models

‍vs GPT-5.1: GPT-5.1 Codex Mini is specialized for coding workflows with advanced code generation, debugging, refactoring, and code review capabilities; it includes multimodal inputs for UI work and dynamic reasoning effort control. GPT-5.1 focuses on broader natural language understanding and general reasoning with a larger context window but less code specialization.

vs GPT-5 Codex: Codex Mini offers a more compact, cost-effective alternative with faster response times and lower resource consumption, while GPT-5 Codex provides deeper reasoning and handles more complex engineering tasks with higher accuracy and a larger context window.

vs GPT-4: GPT-5.1 Codex Mini improves coding task performance significantly over GPT-4, showcasing better steerability and specialized code understanding, while GPT-4 still performs strongly in natural language tasks beyond coding.