Grok 4.20

xAI released Grok 4.20 on March 31, 2026, its flagship model featuring a 2 million token context window, $2 per million input tokens and $6 per million output tokens pricing, and toggleable reasoning capabilities. The model includes web search functionality at $5 per 1,000 queries and claims industry-leading speed with low hallucination rates.

xAI's Grok 4.20 scores 48 on Artificial Analysis' Intelligence Index—6 points ahead of Grok 4 but trailing Gemini 3.1 Pro Preview and GPT-5.4 at 57. The model distinguishes itself with a 78% non-hallucination rate on the AA Omniscience test, the highest recorded across any model tested.