Grok 4.1 Fast Reasoning

Grok 4.1 with fast reasoning and vision support.

grok-4-1-fast-reasoning
STABLEGet StartedView uptime
2,000,000 context
Released November 19, 2025
Starting at $0.20/M input tokens
Starting at $0.50/M output tokens
Streaming
Vision
Tools
Reasoning
JSON Output
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All Providers for Grok 4.1 Fast Reasoning

OffRail routes requests to the best providers that are able to handle your prompt size and parameters.

Azure AI Foundry
Context: 2M
Input
$0.2
/M tokens
Cache Read
/M tokens
Output
$0.5
/M tokens
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Frequently asked questions

What is Grok 4.1 Fast Reasoning?

Grok 4.1 with fast reasoning and vision support. You can access it through OffRail's OpenAI-compatible API with automatic provider routing, fallback, and cost analytics.

How much does Grok 4.1 Fast Reasoning cost?

Pricing for Grok 4.1 Fast Reasoning on OffRail starts at $0.20 per million input tokens and $0.50 per million output tokens, depending on the provider. The pricing table above always reflects the current per-provider rates.

What is the context length of Grok 4.1 Fast Reasoning?

Grok 4.1 Fast Reasoning supports a context window of up to 2,000,000 tokens on its largest provider deployment.

Which providers serve Grok 4.1 Fast Reasoning?

Grok 4.1 Fast Reasoning is served by Azure AI Foundry through OffRail. Requests are automatically routed to the best available provider, with fallback when a provider has issues.

Does Grok 4.1 Fast Reasoning support tool calling and structured outputs?

Grok 4.1 Fast Reasoning supports tool (function) calling and soft JSON output, but NOT strict JSON output schema (its upstream provider does not enforce it).

When was Grok 4.1 Fast Reasoning released?

Grok 4.1 Fast Reasoning was released on November 19, 2025.