xAI: Grok 4 Fast
By X Ai
Released: 2025-09-19
X AI Grok 4 Fast, developed by xAI, features 2,000k-token context window. Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model on xAI's [news post](http://x.ai/news/grok-4-fast). Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#controlling-reasoning-tokens) Available at $0.2/1M tokens.
Visit xAI: Grok 4 FastAI-Powered
Leverages advanced AI technology to deliver cutting-edge capabilities and results.
Fast & Efficient
Optimized performance ensures quick results without compromising on quality.
Purpose-Built
Specifically designed for llms tasks and workflows.
X Ai Model Timeline
2,000k tokens context
2,000k tokens context
256k tokens context
256k tokens context
131k tokens context
131k tokens context
131k tokens context
131k tokens context
Specifications
AI Evaluation
Built for deep analytical thinking and multi-step problem solving. Excels at tasks requiring careful logical reasoning and systematic analysis.
Pros
- Competitive pricing ($0.2/1M)
- Massive 2,000k token context
- Advanced logical reasoning
- Multi-modal input support
Cons
- Speed/quality trade-off
- API integration required
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