LiteLLMModels

Grok 4.1 Fast Reasoning API Pricing

As of October 10, 2026, Grok 4.1 Fast Reasoning costs $0.20 per 1M input tokens and $0.50 per 1M output tokens from Azure AI Foundry, the lowest of 2 providers. It has a 128,000-token context window and returns up to 128,000 tokens per response.

By xAIModel ID azure_ai/grok-4-1-fast-reasoningPrices updated Checked
Input
$0.20 / 1M tokens
Output
$0.50 / 1M tokens
Context window
128,000 tokens
Max output
128,000 tokens
Providers
2
Added to LiteLLM
November 2025

Grok 4.1 Fast Reasoning pricing by provider

2 listings across 2 providers. Token prices are in US dollars per 1M tokens. The highlighted row is the price quoted above.

ProviderModel name in LiteLLMInputOutputCache readContext
Azure AI Foundryazure_ai/grok-4-1-fast-reasoning$0.20$0.50–128K
Google Vertex AIvertex_ai/xai/grok-4.1-fast-reasoning$0.20$0.50$0.05128K

What Grok 4.1 Fast Reasoning costs in practice

1,000 requests with 2,000 input and 500 output tokens each

Azure AI Foundry$0.65
Google Vertex AI$0.65

100 long-document requests with 100,000 input and 2,000 output tokens each

Azure AI Foundry$2.10
Google Vertex AI$2.10

Grok 4.1 Fast Reasoning features

Use Grok 4.1 Fast Reasoning with LiteLLM

Call Grok 4.1 Fast Reasoning through the LiteLLM Python SDK, or put it behind the LiteLLM proxy and send OpenAI-format requests to /v1/chat/completions. LiteLLM tracks the cost of every request at these prices.

Python SDK
from litellm import completion

response = completion(
    model="azure_ai/grok-4-1-fast-reasoning",
    messages=[{"role": "user", "content": "Hello!"}],
)
Proxy config.yaml
model_list:
  - model_name: grok-4-1-fast-reasoning
    litellm_params:
      model: azure_ai/grok-4-1-fast-reasoning
      # credentials: see the provider's LiteLLM docs page
Call the proxy
curl http://0.0.0.0:4000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-1234" \
  -d '{
    "model": "grok-4-1-fast-reasoning",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Grok 4.1 Fast Reasoning FAQ

How much does Grok 4.1 Fast Reasoning cost?

Grok 4.1 Fast Reasoning costs $0.20 per 1M input tokens and $0.50 per 1M output tokens from Azure AI Foundry, the lowest of 2 providers.

What is the context window of Grok 4.1 Fast Reasoning?

Grok 4.1 Fast Reasoning has a 128,000-token context window and returns up to 128,000 tokens per response.

Which providers offer Grok 4.1 Fast Reasoning?

Grok 4.1 Fast Reasoning is available from 2 providers through LiteLLM: Azure AI Foundry and Google Vertex AI.

How do I call Grok 4.1 Fast Reasoning with an OpenAI-compatible API?

Use the LiteLLM Python SDK with model="azure_ai/grok-4-1-fast-reasoning", or add the model to the LiteLLM proxy's config.yaml and send requests to /v1/chat/completions from any OpenAI client. LiteLLM tracks the cost of every request at the prices on this page.

What features does Grok 4.1 Fast Reasoning support?

Grok 4.1 Fast Reasoning supports function calling, structured output, image input, reasoning, prompt caching and web search.

When did LiteLLM add Grok 4.1 Fast Reasoning?

Grok 4.1 Fast Reasoning was added to LiteLLM's model price file in November 2025.

Sources

Prices come from LiteLLM's open-source model_prices_and_context_window.json, which LiteLLM uses to calculate the cost of every request. Provider pricing pages:

LiteLLM docs: Azure AI Foundry, Google Vertex AI.

Provider pages: Azure AI Foundry, Google Vertex AI.