How much does the Grok 4.1 Fast API cost?

Grok 4.1 Fast costs $0.2 per million input tokens and $0.5 per million output tokens, with cached input at $0.05 per million. A workload of 10M input and 1.5M output tokens per month costs about $2.75.

What is the context window of Grok 4.1 Fast?

Grok 4.1 Fast supports a context window of 2,000,000 tokens (2M).

Is Grok 4.1 Fast open source?

No — Grok 4.1 Fast is a proprietary model available through xAI's API and partner platforms.

What are the best alternatives to Grok 4.1 Fast?

The closest alternatives by overall capability are Qwen3-Max, GPT-5.5, Gemini 3 Pro, Gemini 2.5 Pro. See the comparison pages for detailed head-to-head breakdowns.

Grok 4.1 Fast

xAI·Nov 2025reasoningproprietary

Grok 4.1 Fast is xAI's speed-and-scale tier and arguably the best long-context bargain on the market: a 2 million token window at budget pricing. It is tuned for agentic tool calling and high-throughput workloads, and its economics make previously impractical patterns — like stuffing an entire corpus into context instead of building RAG — suddenly viable for some teams.

Benchmark results

No verified benchmark results tracked yet for Grok 4.1 Fast. This page is updated as official evaluations are published.

Where it shines

2M-token context at one tenth of typical frontier prices
Strong tool-calling tuned for agent workloads
Very fast time-to-first-token

Alternatives to Grok 4.1 Fast

Qwen3-Max

Alibaba's trillion-parameter API flagship — frontier-adjacent quality with strong agentic tool use at mid-tier prices.

GPT-5.5

OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.

Gemini 3 Pro

Google's November 2025 frontier breakout — 91.9% GPQA Diamond and 37.5% HLE made it the reasoning leader of its generation.

Gemini 2.5 Pro

Google's 2025 workhorse flagship — first mainstream thinking model with a 1M context, still widely deployed.

Frequently asked questions

How much does the Grok 4.1 Fast API cost?: Grok 4.1 Fast costs $0.2 per million input tokens and $0.5 per million output tokens, with cached input at $0.05 per million. A workload of 10M input and 1.5M output tokens per month costs about $2.75.
What is the context window of Grok 4.1 Fast?: Grok 4.1 Fast supports a context window of 2,000,000 tokens (2M).
Is Grok 4.1 Fast open source?: No — Grok 4.1 Fast is a proprietary model available through xAI's API and partner platforms.
What are the best alternatives to Grok 4.1 Fast?: The closest alternatives by overall capability are Qwen3-Max, GPT-5.5, Gemini 3 Pro, Gemini 2.5 Pro. See the comparison pages for detailed head-to-head breakdowns.