Grok

Grok 3 Fast Beta

xAIToken-based
Alias:grok-3-fast-beta
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Compare grok-3-fast-beta API pricing, supported endpoints, capabilities and access options on Modelsell.

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Starting price
Input / Output · 1M
Context
—
Maximum input window
Modalities
→

Pricing by Supplier

xAI
-40%
xAI 官方
Input$5.5$3.3/ 1M
Output$27.5$16.5/ 1M

Capabilities / Supported modalities

StreamingSystem promptFunction callingToolsJSON modeStructured output
Input
Output

Provider & data privacy

Provider
xAIDocs
Tokenizer
Grok tokenizer (BPE)
License
Proprietary (commercial)Proprietary
Data retention69 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 3 Fast Beta

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 3 Fast Beta

从一个具体问题开始对话

Grok 3 Fast Beta 可以解释技术概念、分析文字材料、编写代码草案,也能在多轮交流中调整答案的细节。它适合嵌入知识问答、开发辅助和写作流程:先得到一份可以检查的初稿,再针对缺失条件、表达方式或代码边界继续追问。

处理表格数据时,可以把列名、几行脱敏样例和目标结果一起提供,让它设计清洗步骤、解释公式,或写出处理脚本。处理文字时,则可以要求它保留原文事实,将说明改成客服回复、操作指引或不同长度的摘要。明确哪些内容必须保留,比只说“优化一下”更容易得到可用结果。

如何把代码建议用起来?

先说明语言与运行环境,再给出输入、预期输出和异常样例。可以让模型先解释问题出现的条件,再给出尽量小的修改,最后列出需要运行的测试。生成脚本后,仍需在自己的环境中执行并检查结果;对话中的运行推测不能代替实际测试。

多轮交流要保留什么?

保留已经确认的需求、关键材料和最新结论即可。例如修改数据清洗规则后,应明确旧规则已被替换,避免两套条件同时影响后续答案。涉及近期信息时,提供带日期的资料,让回答有可以核查的依据。

grok-3-fast-beta 是 Grok 3 的历史别名。需要比较实际交互体验时,可用同一组请求观察首字响应和完整结果,结合当前渠道的实际表现选择。

Use cases and prompting

例如要处理订单 CSV,可以输入:

“请用 Python 编写订单清洗函数。列为 order_id、amount、created_at;order_id 重复时保留最新一行,amount 为空时记录为错误,不要自动填零。先解释处理顺序,再给函数和三组测试数据。样例:{脱敏数据}。”

先检查它对重复订单与空值的解释,再要求补充日期格式错误、负数金额等边界情况。把实际执行得到的报错和最小输入回传,继续修正。若用于实时对话,可限制首轮输出长度,把详细说明放到后续追问中,避免一开始就返回过长内容。

API access

API documentation

Code samples

RequestPOST/v1/chat/completions
Example request
Parameters
ParameterTypeDefault / rangeDescription
temperature
number
=10 ~ 2
Sampling temperature; lower is more deterministic
top_p
number
=10 ~ 1
Nucleus sampling probability mass
max_tokens
integer>= 1Maximum number of tokens in the response
frequency_penalty
number
=0-2 ~ 2
Penalises repetition of frequent tokens
presence_penalty
number
=0-2 ~ 2
Encourages introducing new topics
stop
array—Up to 4 strings that stop generation
seed
integer—Deterministic sampling seed (best-effort)
n
integer
=1>= 1
Number of completions to generate
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
logprobs
boolean
=false
Return per-token log probabilities
top_logprobs
integer0 ~ 20Number of top log probabilities returned per token
logit_bias
object—Per-token logit bias map
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
temperature
number
=10 ~ 2
Sampling temperature; lower is more deterministic
top_p
number
=10 ~ 1
Nucleus sampling probability mass
max_tokens
integer>= 1Maximum number of tokens in the response
frequency_penalty
number
=0-2 ~ 2
Penalises repetition of frequent tokens
presence_penalty
number
=0-2 ~ 2
Encourages introducing new topics
stop
array—Up to 4 strings that stop generation
seed
integer—Deterministic sampling seed (best-effort)
n
integer
=1>= 1
Number of completions to generate
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
logprobs
boolean
=false
Return per-token log probabilities
top_logprobs
integer0 ~ 20Number of top log probabilities returned per token
logit_bias
object—Per-token logit bias map
user
string—End-user identifier for abuse monitoring

Rate limits

SupplierRPMTPMRPD
xAIUnlimitedUnlimitedUnlimited

No restriction

Frequently asked questions about grok-3-fast-beta

What is grok-3-fast-beta?

Compare grok-3-fast-beta API pricing, supported endpoints, capabilities and access options on Modelsell.

How do I call grok-3-fast-beta?

Create an API key with access to grok-3-fast-beta, 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-3-fast-beta 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-3-fast-beta for my project?

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