Grok 4 Fast Reasoning

Name: Grok 4 Fast Reasoning
Brand: xAI
SKU: grok-4-fast-reasoning

[Grok 4.1 Fast is xAI's best agentic tool calling model that shines in real-world use cases like customer support and deep research. 2M context window. Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. Learn more in our docs]

grok-4-fast-reasoning

Open Relay View integration

relay/request.mjsready to route

const completion = await client.chat.completions.create({
  model: "grok-4-fast-reasoning",
  messages: [
    { role: "user",
      content: "Plan a multi-step task" }
  ]
});

CONTEXT200K contextprompt window

MAX OUTPUTN/Aper response

INPUT$0.20 / Mtoken price

OUTPUT$0.50 / Mtoken price

Route configuration_

Choose a supported call format.

Select a format below to view its documentation. Use the displayed converter route when calling through PipeLLM.

ENDPOINThttps://api.pipellm.aiOne base URL for OpenAI Chat Completions, Responses, Anthropic, and Gemini.

SUPPORTED CALL FORMATS

OpenAI/openai/v1/chat/completionsDocs Responses/responses/v1/responsesDocs Anthropic/anthropic/v1/messagesDocs Gemini/gemini/v1beta/models/{model}:generateContentDocs Choose a call format to open its request and response documentation.

MODEL IDgrok-4-fast-reasoningUse this in every request

GOVERNANCEPolicy controlledApprovals and tool rules apply

PROVIDER AVAILABILITY2 routes

Provider	Context	Max output	Discount	Input / M	Output / M
X.AI	200K context	N/A	—	$0.20 / M	$0.50 / M
Grok AI	N/A	N/A	—	$0.20 / M	$0.50 / M

Displayed pricing is per one million tokens and may vary by provider.

SUPPORTED SURFACESactive

input: textinput: imageoutput: texttool use

Relay governs model access with the same routing policy that Lens keeps visible and auditable.