April 17, 2026 — xAI began rolling out Grok 4.3 in beta, marking an update to its flagship large language model lineup. The new model became available to SuperGrok Heavy subscribers on an exclusive basis, with general availability following weeks later. The launch was announced by Elon Musk in a post on X.
Scale and architecture
Grok 4.3 runs on the same 0.5 trillion-parameter scale as its predecessor, Grok 4.20. According to Musk, a separate 1 trillion-parameter model is still in training and is planned for a future release, Grok 4.4.
Performance improvements
Early benchmark results reveal substantial gains, particularly in reasoning and coding tasks. Grok 4.3 demonstrates enhanced capabilities in mathematical problem-solving, logical inference, and software development scenarios — areas where scale improvements in large language models consistently yield measurable advances.
Availability and access
Initially restricted to SuperGrok Heavy subscribers, xAI's premium tier, Grok 4.3 reached general availability on May 2, 2026, with API pricing set at $1.25/$2.50.
Why it matters
The release of Grok 4.3 intensifies competition in the advanced AI market, where performance benchmarks remain a key differentiator even as xAI continues to develop larger models for future releases. The staged rollout — from a subscriber-only beta to general availability — underscores the industry-wide push to refine and scale frontier systems for research, software engineering, and enterprise applications.