When was Grok 4.1 Fast Reasoning released?

xAI released Grok 4.1 Fast Reasoning on 19 Nov 2025. It is available through the Opper gateway.

Does Grok 4.1 Fast Reasoning support zero data retention?

With abuse monitoring, yes. On Google Cloud through the Opper gateway, prompts and outputs are not used for training and are kept only for abuse monitoring.

Where is Grok 4.1 Fast Reasoning hosted?

See the per-route table for Grok 4.1 Fast Reasoning hosting locations and residency details.

Is Grok 4.1 Fast Reasoning trained on prompts and outputs?

No. Every hosting route for Grok 4.1 Fast Reasoning is configured so customer prompts and outputs are not used to train models by default.

Is a GDPR DPA available for Grok 4.1 Fast Reasoning?

Yes. A GDPR Data Processing Agreement is available on at least one route serving Grok 4.1 Fast Reasoning. Contact hello@opper.ai to receive it.

Grok 4.1 Fast Reasoning

by xAI

Released 132 days after Grok 4 · All xAI releases

Grok 4.1 Fast Reasoning was released in November 2025 as xAI's high-throughput reasoning model, pairing extended chain-of-thought with the 2 million token context window and fast inference of the Grok 4.1 Fast line. It generates reasoning before responding, improving accuracy on math, code, and multi-step logic while keeping practical throughput. Compared to the non-reasoning variant, it trades some latency for higher accuracy on harder tasks, making it a fit for problem-solving applications that need both capability and long context. It supports vision, tool use, structured outputs, and function calling across multimodal inputs. Reasoning can be toggled through the API, so the same model line can serve fast direct replies or deeper deliberation depending on the request. It was trained with long-horizon reinforcement learning focused on multi-turn, tool-using scenarios.

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Key info

Input

Output

Features

Context window

Max output

30K

Input price

$0.20 /1M$0.05 cache read

Output price

$0.50 /1M

Released

19 Nov 2025

Zero data retention with abuse monitoring
No training by default
GDPR DPA available

Available routes

Grok 4.1 Fast Reasoning runs on 1 route through the Opper gateway. Compare residency, zero data retention and training posture at a glance, with full data-handling detail per route below.

Provider	Region	Zero data retention	Training	Input	Output	Cache read
Google Cloud	Multi		No	$0.20	$0.50	$0.05

Uptime and availability

Grok 4.1 Fast Reasoning runs on a single route through the Opper gateway today, so its availability is that provider's availability.

99.40%route uptime, last 30 days

Single route, no failover target within this model.

Name a second model in the same request and the gateway tries it on retriable errors, so a busy hour never has to reach your users. Set up a fallback chain.

Measured over the last 30 days from each provider's official status feed via StatusGator. Refreshed hourly. See uptime for every provider Opper monitors.

Data handling per route

Each route hosting Grok 4.1 Fast Reasoning has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.

Google Cloud — Multi-region

Zero data retention with abuse monitoring: prompts and outputs are kept for abuse monitoring only, for a window the provider does not state, and are not used for training. No training on customer data. GLOBAL; SCCs; DPA available.

Zero data retention: With abuse monitoring, window not stated.
Training: No training on customer data.
Logging: Abuse monitoring
Abuse monitoring: On by default, holds flagged content, 90 days, a person can view samples
GDPR DPA: DPA available
Transfer mechanism: SCCs

Benchmarks

Independent benchmark scores — composite indices for reasoning, coding, and math, plus individual eval scores where available.

Global rank#207 of 665 LLMs

TierEfficient

Intelligence Index20.4

Math Index89.3

Reasoning & knowledge

MMLU-Pro

85%

GPQA Diamond

85%

Humanity's Last Exam

19%

Long-context reasoning

74%

Coding

LiveCodeBench

82%

Agentic & tool use

Terminal-Bench Hard

24%

τ²-Bench Telecom

93%

Math & instruction following

AIME 2025

89%

IFBench

53%

See full leaderboard →Benchmarks via Artificial Analysis · View on AA

Get started

Call Grok 4.1 Fast Reasoning through the Opper gateway with one API key. Opper is drop-in compatible with the OpenAI, Anthropic and Google AI SDKs.

Grok 4.1 Fast Reasoning is a premium model on Opper. Sign up needs no credit card: you get an API key straight away and the free models work in the playground and the API. Add a card to use premium models, pay-as-you-go with no minimum.

Set it up with your agent

Copy this and paste it into a coding agent like Claude Code, Cursor or Codex and it'll wire up Opper for you.

Or call it directly

1import OpenAI from "openai";
2
3const client = new OpenAI({
4  apiKey: process.env.OPPER_API_KEY,
5  baseURL: "https://api.opper.ai/v3/compat",
6});
7
8const completion = await client.chat.completions.create({
9  model: "vertexai/grok-4-1-fast-reasoning",
10  messages: [{ role: "user", content: "Hello" }],
11});
12console.log(completion.choices[0].message.content);