Grok 4 Heavy

Grok 4 Heavy is an AI model released by SpaceXAI on Wednesday, Jul 9 2025, the same day as Grok 4.

Grok 4 Heavy — frequently asked questions

When was Grok 4 Heavy released?
Grok 4 Heavy was released by SpaceXAI on Wednesday, Jul 9 2025.
Who made Grok 4 Heavy?
Grok 4 Heavy was built by SpaceXAI. Elon Musk's AI company building the Grok series of models. Founded in 2023 as xAI, now part of SpaceX.
Is Grok 4 Heavy open source?
No. Grok 4 Heavy is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.
What came before and after Grok 4 Heavy?
SpaceXAI's previous tracked release was Grok 4 on Jul 9 2025. It was followed by Grok 2.5 on Aug 23 2025.

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