Grok 4.1 Fast (Reasoning)

Yes. Grok 4.1 Fast (Reasoning) is reachable through an OpenAI-compatible endpoint, so an existing OpenAI SDK client works after pointing the base URL at MixRoute and setting the model parameter to grok-4-1-fast-reasoning. Keep your current request and response handling.

Grok 4.1 Fast (Reasoning) is billed per use and the record publishes no free-tier allowance. The current published rates are input $0.2000 per 1M tokens and output $0.5000 per 1M tokens. Trial credit or promotional quota is tied to your account rather than to the model, so check the console before planning around a free tier.

Before switching production traffic to Grok 4.1 Fast (Reasoning), run a pilot on a representative slice of your traffic and check output quality, latency at peak concurrency, and cost per request. Verify the error and retry behaviour, and confirm the request limits you depend on match your plan.

Reasoning tokens are billed as output on Grok 4.1 Fast (Reasoning), at $0.5 per 1,000,000 token. They are generated before the visible answer and count toward both latency and spend, so a higher reasoning setting costs more even when the final answer is short.

Grok 4.1 Fast (Reasoning) sits alongside o3, o3-2025-04-16, grok-4-0709 in the catalog. Compare them on the dimensions that change your bill and your users’ experience: task quality on your own prompts, latency at your concurrency, context and output limits, and cost per completed task rather than per token.