xAI: Grok 4 Fast
xAI Fast
Model ID: grok-4-fast
Pricing
Input $0.20 / 1M tokens
Output $0.50 / 1M tokens
Cache Read $0.05 / 1M tokens
Specifications
Context Window 2M tokens
Max Output 30K tokens
Family grok-4
Mode chat
Capabilities
StreamingSystem PromptsVisionFunction CallingReasoningJSON Mode