Grok 4.1 Fast

• 🏢 Built by xAI, a SpaceX subsidiary
• 🔧 Top-tier agentic tool-calling and function execution
• 👁️ Multimodal with vision and image analysis
• 📏 1,000,000-token context window
• ⚡ Optimized for low-latency, snappy responses
• 🌍 Web search capability built in

xAI

xAI is an American artificial intelligence company and wholly owned subsidiary of SpaceX. The company develops AI systems under the Grok brand, spanning language models, image generation, and video synthesis. xAI has quickly established itself as a multimodal…

Grok 4.1 Fast is xAI's speed-optimized text model designed to excel at agentic tool-calling workflows. Released in late 2025, it combines reasoning, vision, function calling, and web search into a single low-latency package, making it particularly effective for real-world automation scenarios like customer support pipelines and image analysis tasks. Its massive one-million-token context window allows it to process extensive documents or long conversation histories without truncation.

Within xAI's lineup, Grok 4.1 Fast sits as the dedicated fast-inference option alongside the later Grok 4.20 family, which includes both a standard and multi-agent variant. While Grok 4.20 represents xAI's next-generation flagship, Grok 4.1 Fast remains the go-to choice when latency matters most — trading peak reasoning depth for responsiveness.

This model is best suited for developers building agentic applications that chain multiple tool calls, need quick visual understanding, or require web-grounded answers at interactive speeds. Its combination of multimodal input, function execution, and fast inference makes it a strong fit for production-grade assistants and automation agents.