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Grok 4 Fast Blog

Mar 19, 2026

Grok-4-fast API

Grok-4-Fast is xAI’s new cost-efficient reasoning model designed to make high-quality reasoning and web search capabilities cheaper and faster for both consumer and developer use. xAI positions it as a frontier offering that preserves Grok-4’s benchmark performance while improving token efficiency, and ships two variants tuned for either reasoning or non-reasoning workloads.

Grok 4 Fast API launch: 98% cheaper to run, built for high-throughput search

xAI announced Grok 4 Fast, a cost-optimized variant of its Grok family that the company says delivers near-flagship benchmark performance while slashing the