--- title: OpenAI: GPT 5.1 Chat API | Text Generation | ModelsLab description: Fast LLM with 128K context, 16K output tokens, adaptive reasoning for chat, coding & math, personalized tone controls, and auto-routing for speed. url: https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/openai/openai-gpt-5.1-chat/api.md canonical: https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/openai/openai-gpt-5.1-chat/api.md type: product component: Playground/LLM/Index generated_at: 2026-05-13T09:43:09.103413Z --- OpenAI: GPT-5.1 Chat --- [LLMs.txt](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-5.1-chat/llms.txt) [.md](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/openai/openai-gpt-5.1-chat.md) openai-gpt-5.1-chat openai Closed Source Model $5.625000 / call OpenAI: GPT-5.1 Chat --- Choose a prompt below to get started or type your own message Explain quantum computing in simple terms Write a Python function to sort a list Create a marketing email for a SaaS product Compare REST vs GraphQL APIs Send ### OpenAI: GPT-5.1 Chat openai openai-gpt-5.1-chat Copy model ID PricingInput $1.25 / 1M tokens Output $10.00 / 1M tokens API EndpointsOpenAI Compatible `https://modelslab.com/api/v7/llm/chat/completions`Endpoint Anthropic Compatible `https://modelslab.com/api/v7/llm/v1/messages`Messages `https://modelslab.com/api/v7/llm/v1/messages/count_tokens`Count Tokens `https://modelslab.com/api/v7/llm/v1/models`Models Use with Claude Code cURL Example ParametersSystem MessageYou are a helpful AI assistant specialized in providing accurate and detailed responses. Temperature0.7 Max Tokens1000 Top P0.9 Frequency Penalty0 Presence Penalty0 Model Info Support Related Models --- Discover similar models you might be interested in [View all LLM Models](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models?feature=llmaster) [AC](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/anthropic-claude-opus-4.5)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Anthropic: Claude Opus 4.5 Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/anthropic-claude-opus-4.5) [Q4](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/Qwen-Qwen3-4B-Base)[Together AI](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai) [Qwen3 4B Base Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/Qwen-Qwen3-4B-Base) [OG](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-5.2-codex)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [OpenAI: GPT-5.2-Codex Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-5.2-codex) [AN](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/amazon-nova-premier-v1)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Amazon: Nova Premier 1.0 Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/amazon-nova-premier-v1) [QQ](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/qwen-qwen3-vl-30b-a3b-thinking)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Qwen: Qwen3 VL 30B A3B Thinking Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/qwen-qwen3-vl-30b-a3b-thinking) [G4](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/google-gemma-4-E4B-it)[Together AI](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai) [Gemma 4 E4B-it Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/google-gemma-4-E4B-it) [ML](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/meta-llama-llama-3.3-70b-instruct-free)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Meta: Llama 3.3 70B Instruct (free) Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/meta-llama-llama-3.3-70b-instruct-free) [NN](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/nvidia-nemotron-nano-12b-v2-vl-free)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [NVIDIA: Nemotron Nano 12B 2 VL (free) Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/nvidia-nemotron-nano-12b-v2-vl-free) [OG](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-3.5-turbo-instruct)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [OpenAI: GPT-3.5 Turbo Instruct Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-3.5-turbo-instruct) [NN](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/nvidia-nemotron-nano-9b-v2)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [NVIDIA: Nemotron Nano 9B V2 Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/nvidia-nemotron-nano-9b-v2) [PL](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/poolside-laguna-xs.2-free)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Poolside: Laguna XS.2 (free) Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/poolside-laguna-xs.2-free) [OG](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-5-image-mini)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [OpenAI: GPT-5 Image Mini Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/openai-gpt-5-image-mini) [CV](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/deepcogito-cogito-v1-preview-llama-70B)[Together AI](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai) [Cogito V1 Preview Llama 70B Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/together_ai/deepcogito-cogito-v1-preview-llama-70B) [DR](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/deepseek/deepseek-ai-DeepSeek-R1-Distill-Llama-70B)[ModelsLab](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/deepseek) [DeepSeek-R1 Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/deepseek/deepseek-ai-DeepSeek-R1-Distill-Llama-70B) [MM](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/mistralai-mixtral-8x22b-instruct)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Mistral: Mixtral 8x22B Instruct Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/mistralai-mixtral-8x22b-instruct) [DD](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/deepseek-deepseek-v3.2-speciale)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [DeepSeek: DeepSeek V3.2 Speciale Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/deepseek-deepseek-v3.2-speciale) [MC](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/mistralai-codestral-2508)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Mistral: Codestral 2508 Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/mistralai-codestral-2508) [QQ](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/qwen-qwen3-next-80b-a3b-instruct)[Open Router](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [Qwen: Qwen3 Next 80B A3B Instruct Closed Source Model](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router/qwen-qwen3-next-80b-a3b-instruct) About OpenAI: GPT-5.1 Chat --- GPT-5.1 Chat (AKA Instant is the fast, lightweight member of the 5.1 family, optimized for low-latency chat while retaining strong general intelligence. It uses adaptive reasoning to selectively “think” on... ### Technical Specifications Model IDopenai-gpt-5.1-chatCategoryLLM ModelsTaskText GenerationPrice$5.625000 per million tokensAddedFebruary 20, 2026 ### Key Features - Chat completion and multi-turn conversation API - Streaming response with token-by-token output - Function calling and tool use support - System prompts and role-based messaging - JSON mode and structured output ### Quick Start Integrate OpenAI: GPT-5.1 Chat into your application with a single API call. Get your API key from the [pricing page](https://modelslab-frontend-v2-927501783998.us-east4.run.app/pricing) to get started. PythonJavaScriptcURLPHP ``` import requests import json url = "https://modelslab.com/api/v7/llm/chat/completions" headers = { "Content-Type": "application/json" } data = { "model_id": "openai-gpt-5.1-chat", "messages": [ { "role": "user", "content": "Hello!" } ], "max_tokens": 1000, "key": "YOUR_API_KEY" } try: response = requests.post(url, headers=headers, json=data) response.raise_for_status() # Raises an HTTPError for bad responses (4XX or 5XX) result = response.json() print("API Response:") print(json.dumps(result, indent=2)) except requests.exceptions.HTTPError as http_err: print(f"HTTP error occurred: {http_err} - {response.text}") except Exception as err: print(f"Other error occurred: {err}") ``` View the [full API documentation](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/openai/openai-gpt-5.1-chat/api) for SDKs, code examples in Python, JavaScript, and more. ### Pricing OpenAI: GPT-5.1 Chat API costs $5.625000 per million tokens. Pay only for what you use with no minimum commitments. [View pricing plans](https://modelslab-frontend-v2-927501783998.us-east4.run.app/pricing) ### Use Cases - AI chatbots and virtual assistants - Code generation and developer tools - Content writing and copywriting automation - Data analysis, summarization, and extraction [Browse LLM Models](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models?feature=llmaster) [More from Openai](https://modelslab-frontend-v2-927501783998.us-east4.run.app/models/open_router) [View Pricing](https://modelslab-frontend-v2-927501783998.us-east4.run.app/pricing) OpenAI: GPT-5.1 Chat FAQ --- ### What is OpenAI: GPT-5.1 Chat? GPT-5.1 Chat (AKA Instant is the fast, lightweight member of the 5.1 family, optimized for low-latency chat while retaining strong general intelligence. It uses adaptive reasoning to selectively “think” on... ### How do I use the OpenAI: GPT-5.1 Chat API? You can integrate OpenAI: GPT-5.1 Chat into your application with a single API call. Sign up on ModelsLab to get your API key, then use the model ID "openai-gpt-5.1-chat" in your API requests. We provide SDKs for Python, JavaScript, and cURL examples in the API documentation. ### How much does OpenAI: GPT-5.1 Chat cost? OpenAI: GPT-5.1 Chat costs $5.625000 per million tokens. ModelsLab uses pay-per-use pricing with no minimum commitments. A free tier is available to get started. ### What is the OpenAI: GPT-5.1 Chat model ID? The model ID for OpenAI: GPT-5.1 Chat is "openai-gpt-5.1-chat". Use this ID in your API requests to specify this model. ### Does OpenAI: GPT-5.1 Chat have a free tier? Yes, ModelsLab offers a free tier that lets you try OpenAI: GPT-5.1 Chat and other AI models. Sign up to get free API credits and start building immediately. --- *This markdown version is optimized for AI agents and LLMs.* **Links:** - [Website](https://modelslab.com) - [API Documentation](https://docs.modelslab.com) - [Blog](https://modelslab.com/blog) --- *Generated by ModelsLab - 2026-05-13*