xAI: Grok 4 Fast
X-AI Developer Architecture Profile
Intelligence (ELO)1120Chatbot Arena Verified
Max Context2,000,000Tokens
API Cost / 1M$0.70Blended Prompt + Completion
Model Capabilities
- Reasoning
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)
Granular Pricing Matrix
Input Tokens (Prompt)$0.20 / 1M
Output Tokens (Completion)$0.50 / 1M
Pricing data via OpenRouter. Sync: 3/16/2026
Evaluate Competitors
VS Engine MatchupxAI: Grok 4 Fast vs Z.ai: GLM 5 TurboVS Engine MatchupxAI: Grok 4 Fast vs Inception: Mercury 2VS Engine MatchupxAI: Grok 4 Fast vs Qwen: Qwen3.5-27BVS Engine MatchupxAI: Grok 4 Fast vs Qwen: Qwen3.5-122B-A10BVS Engine MatchupxAI: Grok 4 Fast vs AionLabs: Aion-2.0VS Engine MatchupxAI: Grok 4 Fast vs Qwen: Qwen3.5 Plus 2026-02-15