xAI

Grok 4 Fast is a high-speed variant of Grok-4, optimized for faster inference while maintaining strong reasoning capabilities. It offers improved throughput and lower latency compared to the standard Grok-4 model.

Grok model for agentic tool use, reasoning, coding, and live assistance

Reasoning Grok for document-heavy analysis and long-horizon tool use

xAI's default Grok for chat, coding, agentic tools, and lower hallucination risk

xAI's latest Grok for chat, coding, agentic tools, and lower hallucination risk

Fast Grok coding model tuned for agentic engineering and iterative edits

Grok Code Fast 1 is a speedy and economical reasoning model that excels at agentic coding. Built from scratch with a brand-new model architecture, it features a pre-training corpus rich with programming-related content and post-training datasets that reflect real-world pull requests and coding tasks. The model has mastered the use of common tools like grep, terminal, and file editing, making it ideal for integration with IDEs. It is exceptionally versatile across the full software development stack and is particularly adept at TypeScript, Python, Java, Rust, C++, and Go.

An advanced language model with improved reasoning capabilities, particularly excelling in coding and mathematical tasks. Features a 128K token context window and enhanced problem-solving abilities compared to its predecessor.

A multimodal model capable of processing text and visual information, including documents, diagrams, charts, screenshots, and photographs. Notable for strong real-world spatial understanding capabilities.

Grok-2 is a frontier language model with state-of-the-art reasoning capabilities, featuring advanced abilities in chat, coding, and reasoning. It demonstrates superior performance in visual math reasoning, document-based question answering, and excels across various academic benchmarks including reasoning, reading comprehension, math, and science.

Grok-2 mini is a smaller, faster variant of Grok-2 that offers a balance between speed and answer quality. While more compact than its larger sibling, it maintains strong capabilities across various tasks including reasoning, coding, and chat interactions.

Grok 3, launched by xAI on February 17, 2025, is an advanced AI model with significantly enhanced capabilities compared to Grok 2, boasting an order of magnitude increase in performance. Trained on a vast dataset that includes legal documents among others, and utilizing a massive compute infrastructure with around 200,000 GPUs in a Memphis data center, Grok 3's training used ten times more compute than its predecessor. It features specialized models like Grok 3 Reasoning and Grok 3 Mini Reasoning for complex problem-solving, and it excels in benchmarks like AIME for mathematics and GPQA for PhD-level science.

Grok 3 Mini is a streamlined version of xAI's Grok 3 AI model, designed for quicker response times while maintaining utility. It's tailored for users who require speed over the comprehensive capabilities of the full Grok 3 model, making it suitable for tasks where rapid information retrieval is key. Grok 3 Mini still leverages the advanced training and data that Grok 3 was built on but offers a lighter, more efficient version for everyday use.

Grok 4, announced by xAI in summer 2025, represents a major leap in AI capabilities, described as 'the smartest AI in the world.' Built on version 6 of xAI's foundation model, it uses 100x more training compute than Grok 2 and 10x more reinforcement learning compute than Grok 3. The model achieves PhD-level performance across all academic disciplines simultaneously, scoring perfect on standardized tests like the SAT and near-perfect on graduate exams like the GRE. Unlike Grok 3, tool usage is built into the training process rather than relying on generalization. Trained using 200,000 GPUs, Grok 4 excels at complex reasoning, mathematical problem-solving, and coding tasks, though it has acknowledged weaknesses in multimodal capabilities that are being addressed in the next version.

Grok 4 Heavy is the multi-agent version of Grok 4, released alongside the standard model in summer 2025. This system spawns multiple Grok 4 agents in parallel that work independently on problems and then collaborate by comparing their solutions, similar to a study group. The agents share insights and tricks they discover, with the system intelligently combining their work rather than simply using majority voting. Grok 4 Heavy uses approximately 10x more test-time compute than regular Grok 4, enabling it to solve significantly more complex problems. On the Humanities Last Exam, it achieves over 50% accuracy on text-only problems, and it scored a perfect result on the AIME 2025 mathematics competition. The system represents a major advancement in multi-agent AI collaboration and reasoning capabilities.