AI Radar

Grok 4

Retired · Language, Multimodal, Reasoning · Milestone

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 the model with reinforcement learning at pretraining scale and to use tools natively; a Grok 4 Heavy version came with a new subscription tier. It was retired from the API on 15 May 2026. [1] [2] [3] Primary source

Timeline of Grok 4 →

Claims and evidence

  • Released Primary source[1]first paragraph [4]July 2025, Jul 9
  • Retired Effective 12:00 PM PT on the xAI API. Primary source[3]first paragraph
  • Status Retiredgrok-4-0709 retired from the xAI API; requests are served by grok-4.3. Primary source[3]list of retired models
  • Replaced by Grok 4.3grok-4-0709 redirects to grok-4.3 with low reasoning effort. Primary source[3]Recommended Replacements
  • Successor of Grok 3 EditorialEditorial link along the main Grok line: the announcement describes Grok 4 as scaling up the reinforcement learning work begun with Grok 3 Reasoning, without calling it a successor. Primary source[1]Scaling Up Reinforcement Learning
  • Change · Reasoning xAI says it ran reinforcement learning at pretraining scale, with over an order of magnitude more compute than it had used before.Compared with Grok 3 Primary source[1]Scaling Up Reinforcement Learning
  • Change · Tool use Trained with reinforcement learning to use tools natively, such as a code interpreter, web browsing and X search.Compared with Grok 3 Primary source[1]Native Tool Use
  • Change · Modality xAI describes the Grok 4 API as offering multimodal understanding of text and images; the grok-3 API model page listed text input only.Compared with Grok 3 Primary source[1]Grok 4 API [5]At a glance, Modalities
  • Change · Availability A Grok 4 Heavy version using parallel test-time compute was offered through a new SuperGrok Heavy subscription tier.Compared with Grok 3 Primary source[1]Grok 4 Heavy
  • Input text, imageThe announcement describes multimodal understanding across text and vision for the Grok 4 API. Primary source[1]Grok 4 API
  • Feature Tool useTrained with reinforcement learning to use tools such as a code interpreter, web browsing and X search. Primary source[1]Native Tool Use
  • Context window 256,000 tokens Primary source[1]Grok 4 API
  • Parameters Not disclosedNot disclosed by xAI. No claim madeNo source
  • Access consumer app, API Primary source[1]first paragraph [4]July 2025, Jul 9 [2]section 1 Introduction [6]aug-29-2025

Lineage

Predecessors

Successors

Based on

Not derived from another model.

Variants and derived

None recorded.

Siblings

None recorded.

All ancestors

All descendants

Variants

Grok 4 Heavy

Same dates as Grok 4.

  • Variant Inline variant in this record.xAI presents it as a version of Grok 4 that uses parallel test-time compute to consider several hypotheses at once; it was offered through the new SuperGrok Heavy subscription tier. Primary source[1]first paragraph; Grok 4 Heavy

Differs in:

  • Access: consumer app Evidence not assessed [1]first paragraph; Grok 4 Heavy

Related AI Radar coverage

AI Radar coverage starts in June 2026; no coverage linked yet.

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