Requesty
xAI Corp.

grok-4-fast

xAI's latest advancement in cost-efficient reasoning models

Tool callingCachingWeb searchJSON schema
Try grok-4-fastCompareDocs

Specifications

Context window2M tokens
Max outputβ€”
API typechat
AddedOct 16, 2025
Model IDxai/grok-4-fast
Data retentionYes (30 days)
Used for trainingUnknown
Provider locationπŸ‡ΊπŸ‡Έ US
Privacy policyxAI Privacy Policy→

Benchmarks

Released 2025-09-19
Coding Indexcoding
27.4%

Artificial Analysis Coding Index β€” a composite of coding evaluations including LiveCodeBench, SciCode and Terminal-Bench.

GPQA Diamondreasoning
84.7%

Graduate-level physics, chemistry & biology questions designed to resist Googling.

Intelligence Indexreasoning
35.1%

Artificial Analysis Intelligence Index β€” a composite of multiple evaluations measuring overall model capability.

Scores are sourced from official model cards, Artificial Analysis, and public leaderboards. Benchmarks measure specific skills and do not capture every aspect of model quality β€” always test on your own workload.

Pricing

Input / 1M
$0.20
Output / 1M
$0.50
Cache write / 1M
$0.20
Cache read / 1M
$0.05
Estimated cost
100K input + 10K output$0.0250
1M input + 100K output$0.25
10M input + 1M output$2.50

Requesty charges exactly what the upstream provider charges β€” no markup, no per-request fees. Prompt caching and smart routing can reduce effective cost by 30-80%.

Quickstart

Drop-in compatible with the OpenAI SDK. Change the base URL, swap in your Requesty API key, and set the model to xai/grok-4-fast.

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from openai import OpenAI

client = OpenAI(
    api_key="YOUR_REQUESTY_API_KEY",
    base_url="https://router.requesty.ai/v1",
)

response = client.chat.completions.create(
    model="xai/grok-4-fast",
    messages=[
        {"role": "user", "content": "Explain quantum computing in one paragraph."},
    ],
)

print(response.choices[0].message.content)

Other xAI Corp. models

grok-build-0.1
256K ctx$1.00/1M
grok-4.3
1M ctx$1.25/1M
Coding 41
grok-4.2-beta
2M ctx$2.00/1M
grok-4-1-fast-non-reasoning
2M ctx$0.20/1M
grok-4-1-fast-reasoning
2M ctx$0.20/1M
grok-4-fast-non-reasoning
2M ctx$0.20/1M

Frequently asked questions

How much does grok-4-fast cost?
grok-4-fast is priced at $0.20 per million input tokens and $0.50 per million output tokens when accessed via Requesty. Prompt caching is supported, which can cut effective input cost by up to 90% on repeated context. Requesty charges exactly what the upstream provider charges β€” we don't add markup.
What is the context window of grok-4-fast?
grok-4-fast has a context window of 2M tokens. That's roughly 2,667 words of input you can fit in a single prompt.
How does grok-4-fast perform on benchmarks?
grok-4-fast scores 89.7% on Math Index, 89.7% on AIME 2025, 85.0% on MMLU Pro. See the full benchmark chart above for results across MMLU Pro, GPQA Diamond, SWE-Bench Verified, HumanEval, MATH, AIME, MMMU, and LiveBench.
What can grok-4-fast do?
grok-4-fast supports tool calling, prompt caching, web search, structured outputs (JSON schema). You can call it through any OpenAI-compatible client by pointing base_url to Requesty.
How do I use grok-4-fast with the OpenAI SDK?
Install the OpenAI SDK, set base_url to "https://router.requesty.ai/v1", set your API key to your Requesty key, and set the model to "xai/grok-4-fast". The Quickstart above shows Python, JavaScript and cURL snippets.

Access grok-4-fast through Requesty

One API key, 400+ models, OpenAI-compatible. No markup on provider prices, automatic failover, and smart caching built-in.

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