AI Radar

xAI models

xAI, which also does business as SpaceXAI, is the developer of the Grok AI models and assistant. Announced in July 2023, it says its mission is to accelerate human scientific discovery and that it builds AI to understand the universe. It operates a GPU supercomputer named Colossus. In February 2026 it reported that SpaceX had acquired the company.

Chronology

  1. 2026

    6 models
    1. Released
      Grok · Language, Multimodal, Reasoning Grok 4.7

      Grok 4.7 is a language model in xAI's Grok line for text and image input, released on 21 September 2026 on the xAI API, in Cursor and in Grok Build, where it is the default model, and through…

      • Uses a new, larger base model than Grok 4.6; xAI gives no parameter count.
      • xAI describes a longer reinforcement learning run on a harder task mix, weighted toward problems that take many hours.
      Primary source Available · 1 news item
    2. Released
      Grok · Language, Multimodal, Reasoning Grok 4.6

      Grok 4.6 is a language model in xAI's Grok line for text and image input, released on 12 August 2026 on the xAI API, in Cursor and Grok Build, and later on Amazon Bedrock, Google's Model Garden and…

      • Longer supplemental training with curated model-generated reasoning and engineering data and an improved optimizer; Grok 4.5 was used to regenerate its fine-tuning trajectories.
      • Reinforcement learning extended to environments for kernel optimization, web development and computer-aided design.
      Primary source Available · 6 news items
    3. Released
      Grok · Language, Multimodal, Reasoning, Code Grok 4.5

      Grok 4.5 is a language model in xAI's Grok line for text and image input, launched on 16 July 2026 in xAI's Grok Build coding agent, in Cursor and on the xAI API, and from 22 July in the Grok apps…

      • Developed with Cursor; the model card says it received supplemental training on anonymized Cursor workflow data.
      • The model card gives a pretraining cutoff of January 2026.
      Primary source Available · 4 news items
    4. Released
      Grok · Language, Multimodal, Reasoning, Code Grok Build 0.1

      Grok Build 0.1 is an xAI coding model trained for agentic coding, including web development, debugging and MCP support, and the model behind xAI's Grok Build coding agent. It takes text and images…

      Primary source Available · no news linked
    5. Released
      Grok · Language, Multimodal, Reasoning Grok 4.3

      Grok 4.3 is a language model in xAI's Grok line that takes text and images and returns text, rolled out as a beta in the Grok apps on 17 April 2026 and also offered on the xAI API and on Amazon…

      • xAI describes it as a newly pre-trained model at the same scale as Grok 4.20, with an improved architecture.
      • xAI gives a knowledge cutoff of December 2025.
      Primary source Available · no news linked
    6. Released
      Grok · Language, Multimodal, Reasoning Grok 4.20

      Grok 4.20 is a language model in xAI's Grok line that takes text and images and returns text, first released as a beta in the Grok apps in February 2026 and on the xAI API in March 2026 as separate…

      • Can run as a single agent or as a multi-agent system in which several agents work on one request and a leader agent returns the final answer.
      Primary source Available · no news linked

  2. 2025

    7 models
    1. Released
      Grok Fast · Language, Reasoning Grok 4.1 Fast

      Grok 4.1 Fast is an xAI tool-calling model released on the xAI API on 19 November 2025 together with the Agent Tools API, as reasoning and non-reasoning model ids with a 2-million-token context…

      • Trained with reinforcement learning in simulated environments with tools from dozens of domains, and launched with the server-side Agent Tools API.
      • Long-horizon multi-turn reinforcement learning aimed at steady performance across the full 2-million-token window; the window size is unchanged.
      Primary source Retired · no news linked
    2. Released
      Grok · Language, Reasoning Grok 4.1

      Grok 4.1 is an xAI language model released on 17 November 2025 to all users of grok.com, X and the iOS and Android apps, in Thinking and Non-Thinking configurations. xAI calls it an update to Grok 4…

      • Post-training targeted style, personality, helpfulness and alignment, and xAI says it reduced factual hallucinations on information-seeking prompts.
      • Training adds a targeted mid-training stage to improve specific knowledge and capabilities.
      Primary source Status unknown · no news linked Some details lack sources
    3. Released
      Grok Fast · Language, Reasoning Grok 4 Fast

      Grok 4 Fast is an xAI reasoning model that xAI describes as cost-efficient, released on 19 September 2025 in the Grok apps, including for free users, and on the xAI API with a 2-million-token…

      • Reasoning and non-reasoning modes run on the same model weights, steered by the system prompt, instead of separate models.
      • Trained end to end with tool-use reinforcement learning to decide when to call tools such as code execution and web or X search.
      Primary source Retired · no news linked
    4. Released
      Language, Code, Reasoning Grok Code Fast 1

      Grok Code Fast 1 is an xAI reasoning model for agentic coding, released on 28 August 2025 on the xAI API and, free for a limited time, through coding tools such as GitHub Copilot and Cursor. xAI…

      Primary source Retired · no news linked
    5. Released
      Grok · Language, Multimodal, Reasoning · Milestone Grok 4

      Grok 4 is an xAI reasoning model with text and image input, released on 9 July 2025 to SuperGrok and Premium+ subscribers and on the xAI API with a 256,000-token context window. xAI says it trained…

      • xAI says it ran reinforcement learning at pretraining scale, with over an order of magnitude more compute than it had used before.
      • Trained with reinforcement learning to use tools natively, such as a code interpreter, web browsing and X search.
      Primary source Retired · no news linked
    6. Released
      Grok mini · Language, Reasoning Grok 3 mini

      Grok 3 mini is a smaller xAI language model, unveiled alongside Grok 3 on 19 February 2025 with a beta reasoning model, Grok 3 mini (Think). xAI presented it as cost-efficient reasoning for STEM…

      • Announced with a beta reasoning model, Grok 3 mini (Think), trained with large-scale reinforcement learning.
      • xAI positions it as cost-efficient reasoning for STEM tasks that do not need as much world knowledge.
      Primary source Status unknown · no news linked Some details lack sources
    7. Released
      Grok · Language, Reasoning · Milestone Grok 3

      Grok 3 is a language model from xAI with a reasoning mode, Grok 3 (Think). It launched as a beta on 19 February 2025 for X Premium and Premium+ users on X and grok.com, became generally available on…

      • Context window of 1 million tokens, which xAI called eight times larger than its previous models; the grok-3 API model page listed 131,072 tokens.
      • Adds a beta reasoning mode, Grok 3 (Think), trained with large-scale reinforcement learning to think for seconds to minutes before answering.
      Primary source Retired · no news linked

  3. 2024

    6 models
    1. Released
      Grok · Language Grok-2 (December 2024 revision)

      The December 2024 revision of Grok-2 is a new version of that xAI language model, released under the same name and rolled out to all X users free of charge from 12 December 2024. xAI also added it…

      • Three times faster than the earlier Grok-2, according to xAI.
      • xAI reports improved multilingual capabilities.
      Primary source Status unknown · no news linked Some details lack sources
    2. Released
      Grok · Language, Multimodal grok-beta

      grok-beta is a preview language model that xAI offered on its API from the start of the API public beta on 4 November 2024, as the provisional name of a new Grok model in the final stages of…

      Primary source Status unknown · no news linked Some details lack sources
    3. Released
      Grok · Language, Multimodal · Milestone Grok-2

      Grok-2 is a language model from xAI with text and vision understanding, released on 13 August 2024 as an early beta on X for Premium and Premium+ subscribers, together with Grok-2 mini, with an…

      • xAI reports improvements in chat, coding and reasoning over Grok-1.5.
      • xAI says it reasons better with retrieved content and is better at tool use.
      Primary source Available · no news linked
    4. Released
      Grok mini · Language Grok-2 mini

      Grok-2 mini is a smaller language model that xAI released alongside Grok-2 on 13 August 2024, describing it as a sibling of Grok-2 that balances speed and answer quality. It launched in beta on X…

      • A smaller sibling of Grok-2 that xAI says balances speed and answer quality.
      • xAI says it improves on its previous model, Grok-1.5.
      Primary source Status unknown · no news linked Some details lack sources
    5. Announced, release date unknown
      Grok · Language, Multimodal Grok-1.5V

      Grok-1.5V is a preview model that xAI announced on 12 April 2024 as its first-generation multimodal model, taking images such as documents, diagrams, charts, screenshots and photographs alongside…

      • Adds image input, such as documents, diagrams, charts, screenshots and photographs, alongside text.
      Primary source Status unknown · no news linked Some details lack sources
    6. Announced, release date unknown
      Grok · Language Grok-1.5

      Grok-1.5 is a language model from xAI, announced on 28 March 2024 for early testers and existing Grok users on X. xAI says it improves reasoning and problem solving over Grok-1, most notably in…

      • Context window raised to 128,000 tokens from 8,192; xAI says this is up to 16 times the previous length.
      • xAI reports better reasoning and problem solving, most notably in coding and maths.
      Primary source Status unknown · no news linked Some details lack sources

  4. 2023

    1 model
    1. Day not given
      Grok · Language · Milestone Grok-1

      Grok-1 is the language model xAI developed for its Grok assistant, announced on 3 November 2023 and first offered as limited early access to users in the United States. It is a 314-billion-parameter…

      Primary source Available · no news linked

Lineage

  1. Grok-1
    Successors
    Grok-1.5
  2. Grok-1.5
    Predecessors
    Grok-1
    Successors
    Grok-2
    Variants and derived
    Grok-1.5V · variant
  3. Grok-1.5V
    Based on
    Grok-1.5 · variant
  4. Grok-2
    Predecessors
    Grok-1.5
    Variants and derived
    Grok-2 (December 2024 revision) · revision
  5. Grok-2 mini
    Successors
    Grok 3 mini
  6. grok-beta

    No recorded relations.

  7. Grok-2 (December 2024 revision)
    Successors
    Grok 3
    Based on
    Grok-2 · revision
  8. Grok 3
    Successors
    Grok 4
  9. Grok 3 mini
    Predecessors
    Grok-2 mini
    Successors
    Grok 4 Fast
  10. Grok 4
    Predecessors
    Grok 3
    Successors
    Grok 4.1
  11. Grok Code Fast 1

    No recorded relations.

  12. Grok 4 Fast
    Predecessors
    Grok 3 mini
    Successors
    Grok 4.1 Fast
  13. Grok 4.1
    Predecessors
    Grok 4
    Successors
    Grok 4.20
  14. Grok 4.1 Fast
    Predecessors
    Grok 4 Fast
  15. Grok 4.20
    Predecessors
    Grok 4.1
    Successors
    Grok 4.3
  16. Grok 4.3
    Predecessors
    Grok 4.20
    Successors
    Grok 4.5
  17. Grok Build 0.1

    No recorded relations.

  18. Grok 4.5
    Predecessors
    Grok 4.3
    Successors
    Grok 4.6
  19. Grok 4.6
    Predecessors
    Grok 4.5
    Successors
    Grok 4.7
  20. Grok 4.7
    Predecessors
    Grok 4.6

Families

Not in a family

About the organisation

  • Description xAI, which also does business as SpaceXAI, is the developer of the Grok AI models and assistant. Announced in July 2023, it says its mission is to accelerate human scientific discovery and that it builds AI to understand the universe. It operates a GPU supercomputer named Colossus. In February 2026 it reported that SpaceX had acquired the company. Primary source[1] [2] [3] [4]

Company · https://x.ai · 20 models listed here

Sources

  1. [1] Model Card: Grok 4.5

    Model card · xAI · published

    Provenance
    Primary
    Availability
    Active
    Last checked
    Original ↗ https://media.x.ai/v1/website/4p5-5184fdf9.pdf PDF linked as Grok 4.5 from https://x.ai/safety. The cover gives July 14, 2026 and Revision: 2026-07-20; the file name carries a content hash, so a later revision may get a new URL. The cover date is two days before the announcement of July 16, 2026.

  2. [2] SpaceXAI Brand Guidelines

    Other · xAI · published

    Provenance
    Primary
    Availability
    Active
    Last checked
    Original ↗ https://x.ai/legal/brand-guidelines HTML title is Brand Guidelines; the page heading reads SpaceXAI Brand Guidelines. States that SpaceXAI is the developer of Grok.

  3. [3] Company: Accelerating Scientific Discovery

    Other · xAI

    Provenance
    Primary
    Availability
    Active
    Last checked
    Original ↗ https://x.ai/company Living page, content as seen on 2026-10-01; the site is branded SpaceXAI. Includes a dated milestone timeline (Our path of progress), with Grok 3 API on Apr 3, 2025. The old address https://x.ai/about redirects here. Both returned 403 to a scripted request on 2026-10-02.

  4. [4] xAI joins SpaceX

    Announcement · xAI · published

    Provenance
    Primary
    Availability
    Active
    Last checked
    Original ↗ https://x.ai/news/xai-joins-spacex Short post stating that SpaceX announced it has acquired xAI; links to https://spacex.com/updates#xai-joins-spacex for the full update.