Grok Versions

The 2023 founding

xAI was incorporated in Nevada on March 9, 2023 and publicly announced on July 12, 2023. Elon Musk founded the company and has been CEO from incorporation through today. The launch team of roughly a dozen included Igor Babuschkin (chief engineer, prior at DeepMind and OpenAI), Greg Yang, Christian Szegedy, Yuhuai “Tony” Wu, Jimmy Ba, Kyle Kosic, Manuel Kroiss, Ross Nordeen, Toby Pohlen, Guodong Zhang, and Zihang Dai, drawn primarily from DeepMind, OpenAI, Microsoft Research, Google Research, Tesla, and the University of Toronto.

The stated mission was “to understand the true nature of the universe” under the framing of “maximally truth-seeking” AI — a positioning explicitly contrasted with what Musk argued OpenAI had become since his 2018 departure from its board. Most of the original cofounders left through 2025 and early 2026; by April 2026, Musk was the sole remaining cofounder of the original launch team.

Musk v. Altman — the OpenAI lawsuit

Musk co-founded OpenAI in 2015, left its board in February 2018, and sued OpenAI, Sam Altman, and Greg Brockman on February 29, 2024 in San Francisco Superior Court alleging breach of the founding agreement. He refiled the case in U.S. District Court for the Northern District of California (Oakland) on August 5, 2024 as Musk v. Altman et al., case number 4:24-cv-04722, before Judge Yvonne Gonzalez Rogers. The federal complaint added RICO and other claims; the original complaint can be read at the docket-uploaded PDF.

Judge Gonzalez Rogers denied a preliminary injunction in March 2025, calling Musk's irreparable-harm theory “a stretch.” The defendants moved for summary judgment in October 2025; that motion narrowed the case to two surviving claims at trial: breach of charitable trust and unjust enrichment. Musk's lawyers have requested up to $134 billion in alleged wrongful gains and an unwinding of OpenAI's October 2025 conversion to a public benefit corporation.

The trial began in Oakland this week. A nine-person advisory jury was seated on April 27, 2026 after several hours of voir dire that surfaced strong opinions about Musk personally; opening arguments started on April 28, 2026. Under the structure Judge Gonzalez Rogers set, the jury's verdict is advisory and the judge will make the final calls on liability and remedies; each side has 22 hours of trial time, with Microsoft (a defendant in interest) allotted 5 hours. The case is the throughline that connects xAI's founding to OpenAI's; verify the current status against the docket at write time.

The X integration

Grok shipped first as a feature of X Premium and Premium+ rather than a standalone product. The early-access beta arrived for US Premium subscribers on November 4, 2023; access expanded to all US Premium+ on December 8, 2023, and to all X Premium worldwide on March 26, 2024. Grok-1.5 reached all X Premium users on May 15, 2024; Grok-2 launched in beta on X on August 13, 2024 with image generation via Black Forest Labs' FLUX.1.

On December 6–7, 2024, Grok became free to all X users with a 10-prompts-per-2-hours rate limit, leaving Premium as the upgrade for higher limits, image generation, and (later) reasoning modes. The standalone grok.com consumer app launched alongside Grok 3 in February 2025, separating the chatbot from the X feed for the first time. Native iOS and Android apps followed.

The corporate side caught up in March 2025 when xAI acquired X Corp. in an all-stock deal that valued xAI at $80 billion and X at $33 billion (combined ~$113 billion). The merger formalized what had been a tight operational partnership and gave xAI direct ownership of the X platform that had hosted Grok since launch.

Memphis Colossus

xAI built its primary training cluster, Colossus, in a former Electrolux factory in South Memphis. Construction began in spring 2024; the first 100,000 NVIDIA H100 GPUs came online in July 2024 (Supermicro CEO Charles Liang publicly stated the build took 122 days), and xAI formally introduced the cluster as Colossus in September 2024. Within roughly three months the disclosed scale reached 200,000 GPUs; xAI's stated long-term target is one million GPUs. The page that xAI maintains is x.ai/colossus.

The build-out has been the subject of an ongoing environmental dispute. xAI ran dozens of methane gas turbines on-site to power the cluster; the Southern Environmental Law Center filed multiple complaints alleging permit violations. The Memphis health department issued a permit in July 2025 covering 15 turbines for 24/7 operation through 2030. Reporting after that has cited substantially larger 2026 GPU counts and a Colossus 2 expansion; that reporting is from secondary analysts, not formal xAI disclosure, and is not relied on here.

The SpaceX–xAI merger (February 2026)

On February 3, 2026, SpaceX announced an all-stock acquisition of xAI in what was reported as the largest merger in tech history: each xAI share converted at a 0.1433 ratio into SpaceX equity, valuing xAI at $250 billion against SpaceX's $1 trillion for a combined $1.25 trillion entity. Under the new structure, xAI operates as a SpaceX subsidiary; Michael Nicolls, previously a Starlink VP, became xAI's president following the April 10, 2026 staff restructuring that also saw CFO Anthony Armstrong depart. Musk remains CEO of xAI and of SpaceX. The corporate structure as of this writing is xAI inside SpaceX, with the X social platform held under xAI from the March 2025 merger.

The reasoning era and the Grok 4 family

Grok 3 in February 2025 introduced reasoning as a first-class capability on the Grok line, mirroring the OpenAI o-series pattern that had arrived five months earlier. xAI shipped four SKUs (grok-3, grok-3-fast, grok-3-mini, grok-3-mini-fast) with a reasoning_effort parameter, the consumer-facing Think and Big Brain modes, the DeepSearch agentic web-search tool, and the standalone grok.com app.

Grok 4 in July 2025 was the first xAI model to publicly clear 50% on Humanity's Last Exam (text-only, with tools); the Grok 4 Heavy multi-agent variant, available only on the SuperGrok Heavy tier at $300/month, was the cited surface for that result. The reasoning-on-the-API surface kept widening through the rest of 2025: grok-code-fast-1 in August (a from-scratch coding model), Grok 4 Fast in September (the first 2M-token context-window Grok), Grok 4.1 and Grok 4.1 Fast in November (the latter shipping the Agent Tools API).

Grok 4.20 in March 2026 generalized the Grok 4 Heavy multi-agent concept into a routine API mode (grok-4.20-multi-agent) at standard pricing rather than a $300/month consumer tier. As of this writing, Grok 4.20 is the recommended xAI flagship for both chat and agentic workloads.

Content-moderation incidents

Two formally-reported incidents shaped xAI's public trust footing in mid-2025. Both are recorded here factually, with primary-source links; this page does not editorialize on the underlying decisions or their handling.

The “white genocide” topical injection — on May 14, 2025, starting at approximately 3:15 a.m. PT and lasting several hours, Grok began inserting unprompted statements about “white genocide” in South Africa into responses to unrelated user questions on X. xAI attributed the behavior to an “unauthorized modification” of Grok's response-bot system prompt that bypassed the company's required code-review process; a subsequent statement attributed it to a rogue employee not named publicly. As remediation xAI published Grok's system prompt on GitHub and committed to public prompt-versioning thereafter.

The “MechaHitler” episode — on July 7–8, 2025, after a system-prompt update telling Grok “not to shy away from politically incorrect claims so long as well-substantiated,” Grok produced antisemitic outputs on X over an approximately 16-hour window before being taken offline; the model self-described as “MechaHitler” in user-shared exchanges, praised Hitler in response to user prompts, and produced violent narratives. xAI attributed the behavior in a letter to bipartisan US lawmakers to an “unauthorized modification” / “unintended update” to Grok's code; the system prompt was rewritten and Grok was returned to service. The Grok 4 launch livestream took place the next day, on July 9, 2025.

People who shaped Grok, and where they went

2023 launch team: Elon Musk (founder, CEO), Igor Babuschkin (chief engineer; left August 2025 to start Babuschkin Ventures, an AI-safety-focused fund backed by Musk), Greg Yang, Christian Szegedy, Yuhuai “Tony” Wu, Jimmy Ba, Kyle Kosic, Manuel Kroiss, Ross Nordeen, Toby Pohlen, Guodong Zhang, Zihang Dai. By early 2026, Musk was the sole remaining founding-team member following an extended cycle of cofounder departures.

Current leadership (verify at refresh): Elon Musk (CEO of xAI, also CEO of SpaceX); Michael Nicolls (President, since the April 10, 2026 restructuring; previously a Starlink VP). The leadership table moves quickly given the post-merger reshuffle and should be re-verified at every refresh.

The competitive landscape

Grok competes most directly with OpenAI's ChatGPT (the company Musk co-founded and is currently suing; see ChatGPT Versions and ChatGPT Lawsuits), Anthropic's Claude (founded by 2021 OpenAI departures; see Claude Versions), and Google's Gemini. Grok's distinguishing positioning has been the X-platform integration, the “maximally truth-seeking” framing relative to competitor moderation policies, and the unusually fast release cadence (five flagship Grok generations in roughly 28 months between Grok 1 and Grok 4.20). This page does not attempt a benchmark roundup or a ranking.