X-ai
xAI: Grok 4 Fast
Symphonietta
Symphony
REGULAR
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)
Input Price
4 credits/M
per million tokens
Output Price
10 credits/M
per million tokens
Context Window
2,000,000
tokens
Capabilities
Input
TEXT-AND-IMAGE
Output
TEXT