GPT-5.1 Chat Latest

GPT-5.1 Chat API Overview

GPT-5.1 Chat Latest is OpenAI's advanced conversational AI model delivering enhanced intelligence, warmth, and responsiveness. Designed as a low-latency, highly interactive model, it offers users a natural, engaging, and adaptive conversational experience. The model introduces adaptive reasoning to decide when to respond instantly or when to thoughtfully process complex queries, making it efficient for both simple and challenging interactions.

Technical Specifications

• Model family: GPT-5.1 (iteration on GPT-5 architecture)
• Context: Up to 128K tokens
• Reasoning: Adaptive reasoning capabilities, balancing computational resources with task requirements
• Latency: Instant optimized for low latency

Performance Benchmarks

GPT-5.1 Chat prioritizes a seamless, rapid-fire chat style by processing straightforward math and logic almost without a break.

Key Features

• Warmer and more conversational: GPT-5.1 Instant provides a friendly, engaging tone by default, enhancing user satisfaction.
• Adaptive reasoning: Intelligently allocates extra computation on difficult tasks, balancing speed with depth.
• Improved instruction-following: More accurate handling of multi-step prompts with clearer, less technical responses.
• Customization options: Expanded presets including Professional, Friendly, Candid, Quirky, Efficient, Nerdy, Cynical for tailored tone.

GPT-5.1 API Pricing

• Input: $1.3125 per 1M tokens
• Cached Input: $0.13125 per 1M tokens
• Output: $10.50 per 1M tokens

Code sample

Comparison with Other Models

vs GPT-5: GPT-5.1 offers a warmer, more conversational default tone and better instruction-following, while GPT-5 is more formal and less adaptive. GPT-5.1’s adaptive reasoning enables faster responses on simple tasks and deeper persistence on complex ones, enhancing user experience beyond the robust reasoning of GPT-5.

vs Anthropic Claude: GPT-5.1 emphasizes a balance of intelligence and empathy with conversational warmth, whereas Anthropic Claude prioritizes safety-first, conservative tone and ethical safeguards. Claude may have moderate reasoning strengths, but GPT-5.1’s adaptive reasoning and custom tone presets provide a more flexible and engaging user interaction.

vs Google Gemini: GPT-5.1 focuses on optimized conversational latency and adaptive reasoning targeted for chat and voice assistants, while Google Gemini emphasizes multimodality and broad contextual understanding for diverse AI applications. Gemini’s safety and multimodal capabilities are strong, but GPT-5.1 leads in reactivity and conversational customization.