In plain words
xAI is a company, not an app. People meet its work through Grok, a chatbot that answers questions, writes and makes images. Grok is the product. xAI is the team and the computers that build it.
Elon Musk started xAI in 2023 with a small group of researchers. Its job is to train large language models, the kind of AI behind Grok. To do that it built a huge group of GPUs in a single building, a training cluster called Colossus, in Memphis in the United States.
What makes xAI unusual is how often its shape has changed. It merged with X, the social network once called Twitter, and then became part of Musk's rocket company, SpaceX. Its name has changed too. As of November 2026 it is part of SpaceX and goes by the name SpaceXAI.
Everyday example
A restaurant brand and its kitchen
You know a dish by its name on the menu, not by the kitchen that cooks it. Grok is the dish people order. xAI is the kitchen: the cooks, the recipes and the big ovens. The kitchen can be bought by a bigger group and renamed, and the dish still comes out with the same name.
Where the example breaks: A kitchen follows recipes people wrote. xAI's models learn their own patterns from huge amounts of text, so even their makers cannot fully predict every answer they give.
How it actually works
Making a model like Grok takes three ingredients: data, computing power and people who know how to train it. xAI's story is mostly about the second.
Train on a huge computer
A large language model learns by reading enormous amounts of text and adjusting billions of numbers called parameters. That takes thousands of GPUs running for weeks. xAI built its Colossus cluster in Memphis in 122 days and brought it online in September 2024.
Turn the model into an assistant
A freshly trained model only continues text. xAI then trains it further on example conversations and human ratings so it answers questions and follows instructions. See RLHF and fine-tuning.
Plug it into products
The model reaches people through Grok's app and website, inside X, where users can tag Grok in a thread, and through an API that other companies use in their own software.
Release new versions often
xAI ships new Grok models every few months. In March 2024 it also released the weights of its first model, Grok-1, so anyone could download it. Later flagship models stayed closed.
- Founded
- 9 March 2023 by Elon Musk and 11 researchers; announced publicly on 12 July 2023
- Main product
- Grok, a chatbot and model family, launched in November 2023
- Merged with X
- 28 March 2025, when xAI took over X Corp in an all-stock deal
- Supercomputer
- Colossus, Memphis, Tennessee, online from September 2024
Colossus has drawn local criticism over the gas generators that power it. That debate about AI's power needs is covered on AI energy use.
Questions people ask
Is xAI the same as Grok?
Who owns xAI?
Elon Musk founded it. On 2 February 2026 SpaceX acquired xAI, and in May 2026 Musk said it would stop being a separate company. As of November 2026 it runs as SpaceX's AI business under the name SpaceXAI.
Is xAI the same as explainable AI (XAI)?
No. In research papers, "XAI" often means explainable AI: methods for showing why a model gave an answer. That idea has its own page, explainability. xAI with a small x is Musk's company.
What is Colossus?
Colossus is xAI's training cluster in Memphis, Tennessee: a building full of GPUs wired together to train Grok models. It was built in 122 days and came online in September 2024.
Is xAI's Grok open source?
Partly, and only older models. xAI released the weights of Grok-1 in March 2024 under the Apache 2.0 licence. Its newer models are used through Grok's apps and API, without downloadable weights.
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