Grok 4.3
Grok 4.3 is a xAI reasoning model with an improved architecture and a December 2025 knowledge cutoff, matching the scale of Grok 4.20 within a context window of 1M tokens.
import { streamText } from 'ai'
const result = streamText({ model: 'xai/grok-4.3', prompt: 'Why is the sky blue?'})About Grok 4.3
Grok 4.3 was released April 30, 2026 as xAI's next reasoning model in the Grok family. It matches the scale of Grok 4.20 while refining the underlying architecture, and ships with a December 2025 knowledge cutoff so factual recall is closer to current events than earlier Grok generations.
The model targets reasoning-heavy workloads: mathematical problem solving, code analysis, multi-step planning, and tasks where structured thinking improves answer quality. It supports tool use, vision input, file input, and web search, which makes it suitable for agentic systems that combine reasoning with external context. Implicit caching helps keep costs predictable on repeated prefixes within the context window of 1M tokens.
Grok 4.3 produces up to 1M tokens per response, which leaves room for long reasoning traces alongside the final answer. See the pricing panel on this page for current input and output rates.