Grok search is different from every other AI search engine in one way: it can read X. Alongside the open web, Grok searches posts, users and threads on X in real time, which makes it the assistant most shaped by what people are saying right now. This post covers how Grok search finds and cites sources, how many people use it, and what a brand can do to show up.
How many people use Grok?
The best figure comes from SpaceX, which bought xAI in February 2026. Its S-1 filing says that of about 550 million monthly active users across X and Grok, “approximately 117 million MAUs” used Grok’s AI features as of 31 March 2026[5]. That counts any use of Grok, not only search. Website traffic tells a smaller story: Similarweb put Grok at 2.4% of visits to AI chatbot websites in August 2026[6], but that excludes apps and the Grok built into X, which is where much of its use happens.
How Grok search finds sources
xAI’s developer documentation describes the two tools Grok uses. Web Search “enables Grok to search the web in real-time and browse web pages to find information”, and can be limited to, or kept away from, up to five domains[2]. X Search lets Grok “perform keyword search, semantic search, user search, and thread fetch on X”, filtered by handle and date[3]. Those are the tools xAI offers developers, and they match what Grok’s own answers cite: links to web pages and to posts on X.
| Web Search | X Search | |
|---|---|---|
| What it searches | The web, including browsing pages | Posts, users and threads on X |
| Search types | Real-time web search | Keyword, semantic, user, thread fetch |
| Filters | Up to 5 allowed or 5 excluded domains | Up to 20 allowed or excluded handles, dates |
| Media | Image understanding and image search | Image and video understanding |
Grok DeepSearch
DeepSearch arrived with Grok 3 in February 2025 as what xAI called “our first agent”. It was built to “synthesize key information, reason about conflicting facts and opinions, and distill clarity from complexity”, returning “a concise and comprehensive report” rather than a short answer[1]. xAI’s launch examples included gauging reaction on X to a product launch, which is exactly the kind of question only Grok can answer from live posts. For a brand, Grok DeepSearch is where a long-form comparison of you and your competitors is most likely to be written, and it will quote what people said about you.
What Grok cites
Grok’s API returns citations by default: a list of every URL the search encountered, and inline numbered links in the answer. xAI adds a warning worth taking seriously: “not every URL in this list will necessarily be directly referenced in the final answer”[4]. Appearing in the source list and being used in the answer are two different things, which matters when you measure your visibility.
How to show up in Grok
Grok is one of several engines worth tracking. The best AI search engines guide compares them all, and the Reddit guide covers the other big source of public discussion that AI answers draw on.
Questions people ask
How does Grok search the web?
Through two tools that xAI documents: Web Search, which searches the web in real time and browses pages, and X Search, which runs keyword, semantic and user searches on X and fetches threads. Grok combines what it finds into an answer with citations.
What is Grok DeepSearch?
An agent xAI introduced with Grok 3 in February 2025. xAI described it as built to synthesize key information, reason about conflicting facts and opinions, and produce a concise and comprehensive report, going well beyond a single browser search.
Does Grok cite its sources?
Yes. xAI's API returns a list of every URL the search encountered by default, and inline numbered citations in the answer text. xAI notes that not every URL in the list is necessarily referenced in the final answer.
Can I block Grok in robots.txt?
Not with a documented rule. xAI's documentation does not name a crawler or user agent, so there is no official token to disallow. Names such as GrokBot circulate on third-party lists but are not confirmed by xAI.
How do I show up in Grok search results?
Be findable on both of the sources it searches: crawlable web pages that answer the question directly, and discussion on X, where Grok can search posts, users and threads. An active X account under your brand name helps it connect the two.