Grok

Grok is xAI's family of large language models, developed by Elon Musk's AI company xAI and launched in November 2023. Grok's defining differentiator is real-time access to X (Twitter) data — making it uniquely capable for tasks involving breaking news, trending topics, and social media analysis. The model lineup spans efficient general-purpose models, compact reasoning variants, and frontier-tier models trained on Colossus, xAI's in-house GPU supercluster.

Model generations

Grok 2 (August 2024) introduced multimodal capabilities, image generation via Flux by Black Forest Labs, and significantly improved reasoning over the original Grok 1. Grok 2 Vision models (grok-2-vision-1212) support image understanding and are still available in the API for vision-heavy workloads.

Grok 3 (February 2025) is xAI's third-generation model, trained with 10× the compute of its predecessors on the Colossus supercluster. Grok 3 delivers strong reasoning, mathematics, coding, and instruction-following. It introduced DeepSearch — an extended search-and-reasoning mode that combines web search and X data with multi-step reasoning for deep research tasks. Context window: 131,072 tokens.

Grok 3 Mini is a smaller, cost-efficient variant of Grok 3 designed for tasks that don't require full frontier-tier compute. Available with a standard and a reasoning (high) inference mode that uses extended chain-of-thought reasoning. Grok 3 Mini Reasoning (high) scores competitively on reasoning benchmarks relative to its low cost ($0.30/M input, $0.50/M output). Context window: 131,072 tokens.

Grok 4 (July 2025) and Grok 4 Heavy represent xAI's current frontier. Grok 4 supports up to 256K tokens of context; Grok 4 Fast and Grok 4.1 Fast offer 2-million-token context windows — among the largest available across frontier models. As of May 2026, the latest generally available API model is Grok 4.3, which is recommended for all new integrations. Grok 4.3 is priced at $1.25/M input and $2.50/M output tokens with a 1M token context window.

Access methods

xAI API (api.x.ai): REST API compatible with the OpenAI SDK (drop-in base URL replacement). All models are accessible via the API. Developers receive $25 in free credits upon signup, plus up to $150/month additional credits through xAI's data-sharing program. Billing is per token (input + output) with separate per-call fees for built-in tools (web search, X search, code execution: $2.50–$5.00 per 1,000 calls).

grok.com (consumer product): Grok is accessible as a standalone web and mobile app (iOS, Android). Free tier allows approximately 10 prompts every 2 hours with basic Grok access. Paid consumer tiers (SuperGrok, SuperGrok Heavy) unlock higher rate limits, image generation, and access to the most powerful models.

X / Twitter integration: Grok is embedded in the X platform (formerly Twitter). X Premium ($8/month) and X Premium+ ($40/month) subscribers get Grok access bundled with their X subscription. This gives Grok enormous distribution through X's hundreds of millions of users.