Grok 3 Fast Beta is the speed-optimized variant of xAI's Grok 3 model. It delivers lower latency inference while keeping the same Grok 3 training foundation, with a context window of 131.1K tokens.
import { streamText } from 'ai'
const result = streamText({ model: 'xai/grok-3-fast', prompt: 'Why is the sky blue?'})Grok 3 Fast Beta is the latency-optimized variant within the Grok 3 model family, released February 17, 2025. It shares the same training foundation as the full Grok 3 model, built on the Colossus supercomputer, but is configured for faster inference throughput at the cost of some reasoning depth.
The model maintains a context window of 131.1K tokens and handles the same range of tasks as Grok 3, including code generation, analytical reasoning, and complex instruction following. The speed optimization makes it practical for interactive applications, chatbots, and agent loops where response latency directly impacts user experience.
Grok 3 Fast Beta slots between the full Grok 3 (maximum quality) and Grok 3 Mini (maximum efficiency) in the capability-cost spectrum.