Grok

Grok 4.1 Fast Reasoning

xAIToken-based
Alias:grok-4-1-fast-reasoning
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Compare grok-4-1-fast-reasoning API pricing, supported endpoints, capabilities and access options on Modelsell.

text
Starting price
Input / Output · 1M
Context
—
Maximum input window
Modalities
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Pricing by Supplier

xAI
-40%
xAI 官方
Input$0.2$0.12/ 1M
Output$0.5$0.3/ 1M
Cache Read$0.05$0.03/ 1M

Capabilities / Supported modalities

StreamingSystem promptFunction callingToolsJSON modeStructured outputPrompt cachingReasoning
Input
Output

Provider & data privacy

Provider
xAIDocs
Tokenizer
Grok tokenizer (BPE)
License
Proprietary (commercial)Proprietary
Data retention9 daysNot used for upstream training by default

Performance

Benchmarks

Scores on standardized evaluations. Higher percentages are better — and rank percentile shows

Metrics sourced fromArtificial Analysis 2026-09-30·Grok 4.1 Fast Reasoning

This model is not included in the current benchmark snapshot.

Missing models or measurements are not zero scores.

Benchmark charts preserve the source model selection and reasoning settings. Missing models or measurements are not zero scores, and benchmark cost or speed is not this site’s service commitment.

About Grok 4.1 Fast Reasoning

把检索、判断与后续行动串起来

Grok 4.1 Fast Reasoning 适合需要多步处理的智能体任务。它可以理解目标,判断还缺少哪些信息,在获得工具结果后调整下一步,再将材料整理成清楚的答复。典型用途包括跨资料调研、复杂客服排查,以及需要连续查询多个系统的工作助手。

例如分析某项产品功能的用户反馈,可以先检索不同时间段的讨论,再区分具体故障、体验建议和一般情绪,最后按问题频率与证据完整程度整理结果。需要解释政策或服务规则时,也可以先定位相关条款,再对照用户情况,指出尚缺的条件。

它适合保留较长的对话与资料背景,使前面的约束能够参与后续判断。输入长材料时,给文档加上名称和编号,并明确本轮要回答的问题;要求结论对应证据位置,便于回到原文检查。

工具怎样参与推理?

应用可以提供网页或 X 检索、资料查询、代码执行等工具。模型负责选择调用时机与参数,工具返回真实信息后再继续分析。工具必须实际接入并启用;如果没有检索或执行结果,回答应基于已给材料,而不能假装完成了外部查询。

怎样控制任务范围?

给出完成标准、允许的数据范围和停止条件。例如最多检索哪些来源、哪些问题需要追问、何时应报告信息不足。将工具错误作为结果反馈,帮助模型改用其他步骤,避免围绕失败调用反复尝试。

xAI 官方 API 已将此历史名称重定向至 Grok 4.3;已有集成应按实际可用的工具与参数使用。

Use cases and prompting

例如调研功能反馈,可输入:

“请整理最近两周关于导出功能的反馈。只使用已启用检索工具返回的资料,区分功能缺失、导出失败和使用疑问;每类给出代表性证据与日期。先检查信息是否覆盖不同来源,证据不足时列出待补充问题,不要推算用户总量。”

为应用接入对应检索工具,并保存工具结果继续传入对话。先让模型给出分类依据,再生成建议。需要跨多个资料库查询时,说明各库包含什么信息,避免重复搜索同一内容;最后检查引用是否确实支持结论。

API access

API documentation

Code samples

RequestPOST/v1/chat/completions
Example request
Parameters
ParameterTypeDefault / rangeDescription
reasoning_effort
enum
=medium
Controls how much the model thinks before answering
max_completion_tokens
integer>= 1Maximum tokens including hidden reasoning tokens
stop
array—Up to 4 strings that stop generation
seed
integer—Deterministic sampling seed (best-effort)
stream
boolean
=false
Stream tokens via Server-Sent Events
response_format
object—Force JSON object or schema-conforming output
tools
array—Tool / function declarations the model may call
tool_choice
string
autononerequired
Tool-choice policy or specific tool name
user
string—End-user identifier for abuse monitoring

Replace <YOUR_API_KEY> with the API key from your token settings.

Authentication

All requests must include Authorization: Bearer <TOKEN> header. Anthropic-formatted endpoints accept the x-api-key header instead.

Generate tokens from the Tokens page; you can scope them to specific models, groups, IPs, and rate-limits.

Supported parameters

Generation parameters
ParameterTypeDefault / rangeDescription
reasoning_effort
enum
=medium
Controls how much the model thinks before answering
max_completion_tokens
integer>= 1Maximum tokens including hidden reasoning tokens
stop
array—Up to 4 strings that stop generation
seed
integer—Deterministic sampling seed (best-effort)
stream
boolean
=false
Stream tokens via Server-Sent Events
response_format
object—Force JSON object or schema-conforming output
tools
array—Tool / function declarations the model may call
tool_choice
string
autononerequired
Tool-choice policy or specific tool name
user
string—End-user identifier for abuse monitoring

Rate limits

SupplierRPMTPMRPD
xAIUnlimitedUnlimitedUnlimited

No restriction

Frequently asked questions about grok-4-1-fast-reasoning

What is grok-4-1-fast-reasoning?

Compare grok-4-1-fast-reasoning API pricing, supported endpoints, capabilities and access options on Modelsell.

How do I call grok-4-1-fast-reasoning?

Create an API key with access to grok-4-1-fast-reasoning, then use the exact model ID and a supported endpoint from the API access section. Request fields depend on the selected endpoint.

How is grok-4-1-fast-reasoning priced?

Pricing depends on the selected provider group and the model billing unit. The current input, output, request, or media prices are shown on this page before sign-up.

How should I evaluate grok-4-1-fast-reasoning for my project?

Start with the use cases and prompting guidance on this page, then evaluate the model with representative inputs from your project.