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Grok 4.1 Fast

Grok 4.1 Fast is xAI's best agentic tool calling model that shines in real-world use cases like customer support and deep research. 2M context window. Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#controlling-reasoning-tokens)

Input / 1M tokens
$0.200
Output / 1M tokens
$0.500
Context window
2M tokens
Provider
X Ai
Cached input / 1M
$0.050

Performance

Median streaming throughput and first-token latency measured by Artificial Analysis.

Output tokens / sec
140 t/s
Time to first token
0.40s

Benchmarks

Intelligence, coding, and math indexes plus the underlying evaluation scores.

Intelligence Index
24
Coding Index
20
Math Index
34
MMLU-Pro
74.3%
GPQA
63.7%
HLE
5.0%
LiveCodeBench
39.9%
SciCode
29.6%
MATH-500
AIME

Benchmarks via Artificial Analysis