xAI (X.AI Corp.) is an American artificial intelligence company founded by Elon Musk in March 2023. The company's mission is to build AI that can "understand the true nature of the universe." As of February 2026, xAI is a wholly owned subsidiary of SpaceX following an all-stock acquisition.
xAI was founded by a team of researchers with backgrounds at OpenAI, DeepMind, Google, and Microsoft. The company has rapidly scaled to become one of the most well-funded AI startups in history, raising over $22 billion in total funding.
Key AI products and infrastructure include:
- **Grok models** — xAI's family of large language models, from Grok-1 (open-sourced March 2024) through Grok 4.1 (November 2025), with Grok 4 Heavy offering multi-agent capabilities
- **Grok chatbot** — AI assistant integrated into X (formerly Twitter), available to X Premium subscribers
- **Grok API** — Developer API for building on Grok models
- **Colossus supercomputer** — xAI's massive GPU cluster in Memphis, Tennessee, housing over 1 million H100 GPU equivalents with nearly 2 gigawatts of compute capacity
- **Grok for Government** — Enterprise and government AI solutions, including a $200M U.S. Department of Defense contract
- **X platform** — Social media platform acquired by xAI in March 2025, with 600M+ monthly users across X and Grok
xAI has raised $22.13 billion in total primary funding, with a January 2026 round of $20 billion at a $230 billion valuation. Key investors include Nvidia, Fidelity, BlackRock, Sequoia Capital, Qatar Investment Authority, and Cisco Investments. In February 2026, SpaceX acquired xAI in a deal valuing the combined entity at $1.25 trillion.