--- title: OpenAI: GPT-5.1 — Advanced LLM | ModelsLab description: Access OpenAI: GPT-5.1 API for instant and thinking modes with adaptive reasoning. Generate smarter responses via ModelsLab endpoints today. url: https://modelslab-frontend-v2-927501783998.us-east4.run.app/openai-gpt-51 canonical: https://modelslab-frontend-v2-927501783998.us-east4.run.app/openai-gpt-51 type: website component: Seo/ModelPage generated_at: 2026-05-13T10:35:11.311499Z --- Available now on ModelsLab · Language Model OpenAI: GPT-5.1 Reason Smarter, Respond Faster --- [Try OpenAI: GPT-5.1](/models/open_router/openai-gpt-5.1) [API Documentation](https://docs.modelslab.com) Unlock GPT-5.1 Power --- Dual Modes ### Instant and Thinking Routes queries to GPT-5.1 Instant for speed or Thinking for complex reasoning automatically. Adaptive Reasoning ### Dynamic Think Time Adjusts computation depth per prompt, speeding simple tasks and deepening analysis for hard ones. Context Retention ### 400K Token Window Holds context across long conversations, enabling precise multi-turn interactions. Examples See what OpenAI: GPT-5.1 can create --- Copy any prompt below and try it yourself in the [playground](/models/open_router/openai-gpt-5.1). Code Review “Review this Python function for efficiency and bugs: def fibonacci(n): if n <= 1: return n else: return fibonacci(n-1) + fibonacci(n-2). Suggest optimizations and rewrite with memoization.” Data Analysis “Analyze this sales dataset: Q1: 1200 units, Q2: 1500, Q3: 1100, Q4: 1800. Identify trends, forecast Q5, and recommend strategies using adaptive reasoning.” Tech Summary “Summarize quantum computing advances in 2025, explain key concepts simply, and predict enterprise impacts in a structured report.” Workflow Automation “Design a customer support script for handling refunds: include escalation logic, tone control for empathy, and integration steps for CRM systems.” For Developers A few lines of code. GPT-5.1. One API call. --- ModelsLab handles the infrastructure: fast inference, auto-scaling, and a developer-friendly API. No GPU management needed. - **Serverless:** scales to zero, scales to millions - **Pay per token,** no minimums - **Python and JavaScript SDKs,** plus REST API [API Documentation ](https://docs.modelslab.com) PythonJavaScriptcURL Copy ```

import requests

response = requests.post(
    "https://modelslab.com/api/v7/llm/chat/completions",
    json={
  "key": "YOUR_API_KEY",
  "prompt": "",
  "model_id": ""
}
)
print(response.json())

``` FAQ Common questions about OpenAI: GPT-5.1 --- [Read the docs ](https://docs.modelslab.com) ### What is OpenAI: GPT-5.1 API? OpenAI: GPT-5.1 API provides access to Instant and Thinking models via LLM endpoints. It supports adaptive routing for optimal performance. Use it for automation and complex reasoning tasks. ### How does openai gpt 5.1 model differ from GPT-5? GPT-5.1 adds automatic model routing and adaptive reasoning. It splits into Instant for speed and Thinking for depth. Context window expands to 400K tokens. ### Is OpenAI: GPT-5.1 alternative available? ModelsLab hosts OpenAI: GPT-5.1 model as a direct API alternative. Access full features without OpenAI subscriptions. Integrates seamlessly into workflows. ### What are openai: gpt-5.1 api modes? Instant mode prioritizes low latency for quick responses. Thinking mode allocates more reasoning for multi-step problems. Auto-routing selects based on query complexity. ### Does openai gpt 5.1 api support long contexts? Yes, with 400K token window for extended conversations. Maintains accuracy in multi-turn interactions. Ideal for document analysis and support bots. ### Why use openai: gpt-5.1 model for automation? Reduces token costs and latency via optimizations. Handles diverse tasks from transactional to analytical. Improves throughput in enterprise systems. Ready to create? --- Start generating with OpenAI: GPT-5.1 on ModelsLab. [Try OpenAI: GPT-5.1](/models/open_router/openai-gpt-5.1) [API Documentation](https://docs.modelslab.com) --- *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*