---
title: GPT 5.1 API | Text Generation | ModelsLab
description: Smarter and faster large language model with adaptive reasoning, 128K token context window, dual-mode processing for speed or depth, enhanced coding, and.
url: https://modelslab.com/models/openai/gpt5.1.md
canonical: https://modelslab.com/models/openai/gpt5.1
type: product
component: Playground/LLM/Index
generated_at: 2026-08-25T12:37:58.783524Z
---

GPT 5.1
---

 [LLMs.txt](https://modelslab.com/models/openai/gpt5.1/llms.txt) [.md](https://modelslab.com/models/openai/gpt5.1.md)

GPT 5.1
---

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

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Send

### GPT 5.1

openai gpt5.1

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

Looking for something different?
---

Models that trade off differently against the one you are viewing

### Better quality

Newer flagship models that generally produce stronger results.

[![GPT 5.2](https://images.modelslab.sh/?Image=https://assets.modelslab.ai/generations/2bdd00f4-1692-49d8-a562-72cb1753d0ff.png)](https://modelslab.com/models/openai/gpt-5.2)[OpenAI](https://modelslab.com/models/openai)

 [GPT 5.2](https://modelslab.com/models/openai/gpt-5.2)

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[![GPT-5.1-Codex-Max](https://images.modelslab.sh/?Image=https://assets.modelslab.ai/generations/06356c4c-df09-4ccb-a5c0-629da670f75b.png)](https://modelslab.com/models/openai/gpt-5.1-codex-max)[OpenAI](https://modelslab.com/models/openai)

 [GPT-5.1-Codex-Max](https://modelslab.com/models/openai/gpt-5.1-codex-max)

### Lower cost per run

Open-source models we host, unlimited on the $149/month plan.

[Modelslab: Custom LLM

Popular](https://modelslab.com/models/modelslab/uncensored-chat)[ModelsLab](https://modelslab.com/models/modelslab)

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Open Source Model](https://modelslab.com/models/modelslab/uncensored-chat)

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[![gpt-oss-20b](https://images.modelslab.sh/?Image=https://assets.modelslab.ai/generations/8b2f0440-52cc-4f41-93eb-d31006ad71e2.webp)](https://modelslab.com/models/openai/gpt-oss-20b)[OpenAI](https://modelslab.com/models/openai)

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About GPT 5.1
---

Smarter and faster large language model with adaptive reasoning, 128K token context window, dual-mode processing for speed or depth, enhanced coding, and customizable tones.

### Technical Specifications

Model IDgpt5.1

CategoryLLM Models

TaskText Generation

Price$5.63 per million tokens

AddedNovember 16, 2025

### 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 GPT 5.1 into your application with a single API call. Get your API key from the [pricing page](https://modelslab.com/pricing) to get started.

PythonJavaScriptcURLPHP

```
<code>import requests
import json

url = "https://modelslab.com/api/v7/llm/chat/completions"

headers = {
    "Content-Type": "application/json"
}

data = {
        "model_id": "gpt5.1",
        "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}")</code>
```

### Pricing

GPT 5.1 API costs $5.63 per million tokens. Pay only for what you use with no minimum commitments. [View pricing plans](https://modelslab.com/pricing)

### Use Cases

- AI chatbots and virtual assistants
- Code generation and developer tools
- Content writing and copywriting automation
- Data analysis, summarization, and extraction

[Learn more about GPT 5.1](https://modelslab.com/gpt-51) [Browse LLM Models](https://modelslab.com/models?feature=llmaster) [More from OpenAI](https://modelslab.com/models/open_router) [View Pricing](https://modelslab.com/pricing)

GPT 5.1 FAQ
---

### What is GPT 5.1?

Smarter and faster large language model with adaptive reasoning, 128K token context window, dual-mode processing for speed or depth, enhanced coding, and customizable tones.

### How do I use the GPT 5.1 API?

You can integrate GPT 5.1 into your application with a single API call. Sign up on ModelsLab to get your API key, then use the model ID "gpt5.1" in your API requests. We provide SDKs for Python, JavaScript, and cURL examples in the API documentation.

### How much does GPT 5.1 cost?

GPT 5.1 costs $5.63 per million tokens. ModelsLab plans start at $21/month (Basic), and the $149/month Open Source plan includes unlimited generation on open-source models.

### What is the GPT 5.1 model ID?

The model ID for GPT 5.1 is "gpt5.1". Use this ID in your API requests to specify this model.

### Do I need a paid plan to use GPT 5.1?

Yes. ModelsLab is subscription-based with no free tier — plans start at $21/month (Basic, 3,250 API calls). The $149/month Open Source Unlimited plan includes unlimited generation across open-source models; premium third-party models are billed per call from your wallet.

---

*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 - 2026-08-25*