Grok 4 Fast AI Model Cuts Costs by 98%

xAI has launched Grok 4 Fast, a new AI model designed to deliver high-level reasoning at a fraction of the cost. This model builds on the architecture of Grok 4, focusing on efficiency to make sophisticated AI more accessible for both enterprise and consumer applications.

In benchmark tests, Grok 4 Fast achieves performance comparable to its predecessor while using 40% fewer tokens on average. According to xAI, this efficiency, combined with lower per-token pricing, results in a 98% reduction in cost to achieve the same results as Grok 4 on frontier benchmarks.

Independent analysis from Artificial Analysis confirms that Grok 4 Fast offers a state-of-the-art price-to-intelligence ratio among publicly available models. The model was trained using large-scale reinforcement learning, which enhances its ability to decide when to use tools like code execution or web browsing.

Grok 4 Fast excels in agentic search, seamlessly integrating real-time data from the web and X. It can navigate links, process media including images and videos, and synthesize information rapidly. In LMArena's Search Arena, it ranked first with a significant lead over competitors, demonstrating superior efficiency in real-world tasks.

The model introduces a unified architecture that handles both reasoning and non-reasoning modes within the same framework, steered by system prompts. This reduces latency and token costs, making it suitable for real-time applications where speed and depth are balanced.

Available immediately, Grok 4 Fast is offered to all users, including free tiers, via platforms like OpenRouter and Vercel AI Gateway. Developers can access specialized versions—grok-4-fast-reasoning and grok-4-fast-non-reasoning—each with a 2 million token context window for tailored use cases.

This rollout marks a step toward broader AI democratization, as xAI plans ongoing updates based on user feedback. Future enhancements may include improved multimodal and agentic features, though specifics remain under wraps.