Elon Musk has announced that xAI will make its Grok 4.5 artificial intelligence model available to the public on Thursday.

In a post on X, Musk said the decision was based on “strong positive feedback from customers” who tested the model before its wider release.

Musk described Grok 4.5 as an “Opus-class” AI model, adding that it is faster, more token-efficient, and cheaper to run than comparable models. However, he did not share additional technical details or pricing.
What is Grok 4.5?

Musk said Grok 4.5 is built on xAI’s latest V9 foundation model, which has around 1.5 trillion parameters, with an additional training using data from Cursor, an AI-powered coding assistant. He said early internal tests show Grok 4.5 performs close to, or possibly even better than, Opus, the most powerful AI model from Anthropic.

He added that the model is still improving through reinforcement learning. “RL is continuing to significantly improve the model, and the Grok Build harness gets better every day,” he said.

Grok 4.5, based on our 1.5T V9 foundation model, with Cursor data added in supplemental training, is now in private beta at SpaceX & Tesla. Early evals show performance close to, perhaps exceeding Opus.

RL is continuing to significantly improve the model, and the Grok Build…

— Elon Musk (@elonmusk) June 28, 2026

Grok’s users percentage

The public launch of Grok 4.5 comes at a time when xAI is trying to attract more users to its AI chatbot. According to data from app analytics firm Apptopia, the Grok app’s average daily active users in the US fell by nearly 28% between April and June. During the same period, its share of the AI chatbot market also dropped from 10.6% to 8.7%.

Grok software upgrade

Musk said xAI is also upgrading the software that runs Grok. The company expects major improvements in the coming three months by rewriting parts of Grok’s software in C and C++. Musk also said xAI is optimising Grok to work better with Nvidia’s GB300 AI chips.

OpenAI GPT models

In late June, OpenAI introduced its new GPT-5.6 AI model family, but access was limited to a small group of selected partners for testing before the wider release. The company announced that GPT-5.6 Sol, Terra, and Luna will be made available to the public on Thursday.