Grok 4 Fast 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.
Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. Learn more in our docs
Capabilities
Context Window 2M tokens
Max Output 30k tokens
Inputs
Outputs
Pricing (per 1M tokens)
Input $0.20
Output $0.50
Cache Read $0.05
Cache Write -
Supported Parameters
include_reasoninglogprobsmax_tokensreasoningresponse_formatseedstructured_outputstemperaturetool_choicetoolstop_logprobstop_p