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.
- 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.
| Provider | Model name in LiteLLM | Input | Output | Cache read | Context |
|---|---|---|---|---|---|
| Azure AI Foundry | azure_ai/grok-4-1-fast-reasoning | $0.20 | $0.50 | – | 128K |
| Google Vertex AI | vertex_ai/xai/grok-4.1-fast-reasoning | $0.20 | $0.50 | $0.05 | 128K |
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
- Function calling
- Structured output
- Image input
- Reasoning
- Prompt caching
- Web search
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.
from litellm import completion
response = completion(
model="azure_ai/grok-4-1-fast-reasoning",
messages=[{"role": "user", "content": "Hello!"}],
)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 pagecurl 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 $0.50 per 1M output tokens from Azure AI Foundry, the lowest of 2 providers.
What is the context window of Grok 4.1 Fast Reasoning?
Grok 4.1 Fast Reasoning has a 128,000-token context window and returns up to 128,000 tokens per response.
Which providers offer Grok 4.1 Fast Reasoning?
Grok 4.1 Fast Reasoning is available from 2 providers through LiteLLM: Azure AI Foundry and Google Vertex AI.
How do I call Grok 4.1 Fast Reasoning with an OpenAI-compatible API?
Use the LiteLLM Python SDK with model="azure_ai/grok-4-1-fast-reasoning", or add the model to the LiteLLM proxy's config.yaml and send requests to /v1/chat/completions from any OpenAI client. LiteLLM tracks the cost of every request at the prices on this page.
What features does Grok 4.1 Fast Reasoning support?
Grok 4.1 Fast Reasoning supports function calling, structured output, image input, reasoning, prompt caching and web search.
When did LiteLLM add Grok 4.1 Fast Reasoning?
Grok 4.1 Fast Reasoning was added to LiteLLM's model price file in November 2025.
Sources
Prices come from LiteLLM's open-source model_prices_and_context_window.json, which LiteLLM uses to calculate the cost of every request. Provider pricing pages:
- prices.azure.com/api/retail/prices?$filter=serviceName%20eq%20'Foundry%20Models'%20and%20armRegionName%20eq%20'eastus'%20and%20priceType%20eq%20'Consumption'
- cloud.google.com/gemini-enterprise-agent-platform/generative-ai/pricing
LiteLLM docs: Azure AI Foundry, Google Vertex AI.
Provider pages: Azure AI Foundry, Google Vertex AI.
