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xAI: Grok 4 Fast

x-ai-grok-4-fastx-aiClosed Source Model$0.350000 / call

xAI: Grok 4 Fast

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About XAI: Grok 4 Fast

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model...

Technical Specifications

Model ID
x-ai-grok-4-fast
Category
LLM Models
Task
Text Generation
Price
$0.350000 per million tokens
Added
February 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 XAI: Grok 4 Fast into your application with a single API call. Get your API key from the pricing page to get started.

import requests
import json


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


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


data = {
        "model_id": "x-ai-grok-4-fast",
        "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 for SDKs, code examples in Python, JavaScript, and more.

Pricing

XAI: Grok 4 Fast API costs $0.350000 per million tokens. Pay only for what you use with no minimum commitments. View pricing plans

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 XAI: Grok 4 FastBrowse LLM ModelsMore from X AiView Pricing

XAI: Grok 4 Fast FAQ

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model...

You can integrate XAI: Grok 4 Fast into your application with a single API call. Sign up on ModelsLab to get your API key, then use the model ID "x-ai-grok-4-fast" in your API requests. We provide SDKs for Python, JavaScript, and cURL examples in the API documentation.

XAI: Grok 4 Fast costs $0.350000 per million tokens. ModelsLab uses pay-per-use pricing with no minimum commitments. A free tier is available to get started.

The model ID for XAI: Grok 4 Fast is "x-ai-grok-4-fast". Use this ID in your API requests to specify this model.

Yes, ModelsLab offers a free tier that lets you try XAI: Grok 4 Fast and other AI models. Sign up to get free API credits and start building immediately.