Discover the Power of xAI's Grok 4 Fast

Grok 4 Fast: Multimodal AI with 2M token context window.

Input: text · image Output: text Context: 2,000,000 tokens Release: 2025-09-19

Grok 4 Fast by xAI, released in September 2025, is a cutting-edge multimodal AI model designed to handle both text and image inputs, producing text outputs. With an impressive 2 million token context window, it offers a robust platform for complex data processing. The model is available in two variants: non-reasoning and reasoning, which can be toggled via API parameters. This flexibility allows users to tailor the model's capabilities to their specific needs. Key features include state-of-the-art cost-efficiency and a range of supported parameters like temperature and tool choice, making it a versatile choice for diverse applications.

Use Cases

Here are a few ways teams apply xAI: Grok 4 Fast in practice—from fast drafting to multimodal understanding. Adapt these ideas to your workflow.

Enhance data analysis with large context

Optimize text generation tasks

Integrate image and text processing

Customize reasoning capabilities

Improve cost-efficiency in AI operations

Key Features

A quick look at the capabilities that make this model useful in real projects.

2M token context window

Text and image input support

Reasoning toggle via API

State-of-the-art cost-efficiency

Versatile parameter options

Multimodal text output

Specs

Overview

Vendor
x-ai

Model ID
x-ai/grok-4-fast

Release
2025-09-19

Modalities & context

Input
text · image

Output
text

Context
2,000,000 tokens

Parameters & defaults

Supported parameters: include_reasoning, logprobs, max_tokens, reasoning, response_format, seed, structured_outputs, temperature, tool_choice, tools, top_logprobs, top_p

Defaults: temperature 0.2, top_p 0.95

Benchmark tests: xAI: Grok 4 Fast

We ran this model against a few representative prompts to show its range. Review the outputs below and be the judge.

Text

Prompt:

Write 150 words on how AI might positively upend work, leisure and creativity

### AI's Positive Upend of Work, Leisure, and Creativity Artificial Intelligence (AI) promises to revolutionize human life by enhancing efficiency and unlocking potential across key domains. In **work**, AI automates mundane tasks like data entry and analysis, freeing professionals to focus on innovation and problem-solving. This boosts productivity—imagine engineers designing sustainable cities without sifting through endless simulations—while creating new roles in AI ethics and oversight, fostering inclusive economies with flexible, remote opportunities. For **leisure**, AI curates personalized experiences, from tailored travel itineraries to immersive virtual realities that simulate adventures without environmental impact. By optimizing schedules and predicting downtime needs, it reclaims hours lost to chores, enabling deeper relaxation and social connections, like AI-facilitated global hobby communities. In **creativity**, AI acts as a collaborative muse, generating initial drafts for artists or suggesting novel plot twists for writers, democratizing tools once reserved for elites. It amplifies human ingenuity, sparking breakthroughs in music, design, and storytelling, where diverse voices thrive. Overall, AI upends these spheres by amplifying human strengths, fostering fulfillment in an era of abundance. (148 words)

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Image

Prompt:

Generate an SVG of a pelican riding a bicycle.

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up.end

/ˌəpˈend/

verb

To “upend” means to completely disrupt, overturn, or drastically change the established order or structure of something. It implies a significant shift or alteration that can potentially have far-reaching consequences. When something is upended, it is turned upside down or transformed in a way that challenges conventional norms or expectations. The term often carries a sense of innovation, transformation, and sometimes even a hint of upheaval, indicating that the changes are not just minor adjustments but rather a fundamental reimagining of the status quo.

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