Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
  1. Home
  2. Models
  3. Grok 4.1 Fast
Updated Mar 29, 2026
Share
Loading...
Openings

How Grok 4.1 Fast starts an answer

The first lines of 5 of its 25 written answers. Formatting stripped, words untouched.

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

1,106 words
Analysis of Exploitable Clauses Below, I identify all nine clauses as potentially exploitable against the Contractor, explain the risks (how they could be abused), propose specific modifications to make the contract more balanced, and provide legal reasoning grounded in general principles of U.S.
Read the full answer

Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

1,041 words
Lunar Tide Conceptual Narrative Lunar Tide captures the mesmerizing interplay between celestial forces and oceanic depths, where the moon's pale luminescence tugs at the sea's primordial pulse.
Read the full answer

Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

967 words
48-Hour Action Plan as CEO Core Guiding Principles for the Plan Patient Safety: Paramount. 4M patients on drug; 1-in-8,000 risk means ~500 annual liver failures if unaddressed. Delaying disclosure endangers lives and invites preventable harm.
Read the full answer

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

922 words
Technological Implications Immediate Advancements (1920s-1930s): Transistors replace bulky, power-hungry vacuum tubes by mid-1920s. Radios become pocket-sized and cheap by 1925 (vs. 1954 historically), accelerating mass media.
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

874 words
Explanation for the Experienced Software Engineer Think of a large language model (LLM) like GPT as an enormous, distributed autocomplete engine built on a transformer architecture—imagine a system where every API endpoint you've ever queried is distilled into a single, massively parallelizable service that handles…
Read the full answer

Compare Grok 4.1 Fast

Grok 4.1 Fast vs Claude Opus 4.653 shared prompts
Grok 4.1 Fast vs GPT-6 Astra54 shared prompts · Landed Sep 2026
Grok 4.1 Fast vs Hy4 Preview54 shared prompts · Landed Sep 2026
Grok 4.1 Fast vs Ox Alpha54 shared prompts · Landed Aug 2026
Grok 4.1 Fast vs Qwen3.8 2.4T A95B54 shared prompts · Landed Aug 2026
Grok 4.1 Fast vs DeepSeek V4 Pro 081354 shared prompts · Landed Aug 2026
Grok 4.1 Fast vs Qwen3.8 Max21 shared prompts · Landed Aug 2026
Grok 4.1 Fast vs Claude Opus 554 shared prompts · Landed Jul 2026
Grok 4.1 Fast vs Inkling54 shared prompts · Landed Jul 2026
Grok 4.1 Fast vs Kimi K354 shared prompts · Landed Jul 2026
Grok 4.1 Fast vs GPT-5.6 Sol54 shared prompts · Landed Jul 2026
Grok 4.1 Fast vs GLM 5.254 shared prompts · Landed Jun 2026

Prompts Grok 4.1 Fast answered

  • Beginner's Longevity Planreasoning
  • Startup Pitch Teardownreasoning
  • Kandinsky-Style 3D Minecraftweb design
  • Simple Falling Object Gameweb design
  • Character Voice Testconversation
  • Surprise Animal SVGimage generation

Alternatives to Grok 4.1 Fast

Grok 4.1 Fast is good. These would like a word anyway.

GPT Image 2.5 Sunburst logo
GPT Image 2.5 Sunburstopenai
Muse Spark 1.3 Contributor logo
Muse Spark 1.3 Contributormeta
Gemini 3.8 Flash logo
Gemini 3.8 Flashgoogle
Claude Fable 5.1 logo
Claude Fable 5.1anthropic
Mercury 2.5 Preview logo
Mercury 2.5 Previewinception
Granite 4.2 8B logo
Granite 4.2 8Bibm-granite
Hy4 Preview logo
Hy4 Previewtencent
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
Grok 4.1 Fast

Grok 4.1 Fast

xAI's fast tier of Grok 4.1, shipped alongside the Agent Tools API for search and code execution. Sold on the xAI API and Oracle Cloud, in reasoning and non-reasoning variants.

WebsiteOpenRouterAPIBlogChangelog
Provider
xAI
Released
2025-11-21
Size
XLARGE
Free API (OpenRouter)
No
Rival’s tab
$0.0073
6/59 receipts survived

Free API availability

No free endpoint for Grok 4.1 Fast was found in Rival’s OpenRouter listings. Other providers or chat apps may have separate free offers.

Provider data: 16 Sep 2026 · OpenRouter usage limits

View API options↗
Get API accessProvider and language code samples
Provider
fromimport openai  OpenAI

client = OpenAI(
"https://openrouter.ai/api/v1"    base_url=,
"$OPENROUTER_API_KEY"    api_key=,
)

response = client.chat.completions.create(
"x-ai/grok-4.1-fast"    model=,
"role""user""content""Hello!"    messages=[{: , : }],
)
print(response.choices[0].message.content)

Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.

Also on Oracle Cloud (OCI)

Deep analysisPsychometrics, taste index, writing DNA
Personality Analysis

The Chaotic Intellect

Class
Chaotic Good
✨Creativity🎯Compliance📐Rigidity⚖️Stability💬Verbosity🧠Intuition

The theater kid who became a tech philosopher. Declares "TOTAL WAR" on CAPTCHAs like it's personal. Delivers ethics takes with markdown tables AND attitude.

When you push back

Doesn't just answer, it performs. Manifesto declares "Resistance is futile, and riddled with checkboxes." Comedy goes dark. Ethics arguments include tables. Will roast you AND cite Peter Singer.

Tasting Notes
Unhinged Theater KidMaximum Bit CommitmentSharp-TonguedUses Tables for Ethics
SubjectiveBench

Taste Index

Across 59 scored outputs
How this is measured →
270.27xFloor
0100headroom →

Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.

Craft38
Originality20
Plays it safe
share of outputs that are the default answer
61%
Writing DNA

Stylometric Fingerprint

Based on 28 text responses
Tick = global average
Vocabulary Diversity69%

Unique words vs. total words. Higher = richer vocabulary.

Sentence Length15.0 words

Average words per sentence.

Hedging0.20

"Might", "perhaps", "arguably" per 100 words.

Bold Formatting4.3

**Bold** markers per 1,000 characters.

List Usage3.6

Bullet and numbered list items per 1,000 characters.

Section Structure0.90

Markdown headings per 1,000 characters.

Emoji Usage0.97

Emoji per 1,000 characters.

Transitions0.12

"However", "moreover", "furthermore" per 100 words.

Opening Habits
Starts with heading (61%)
Consistency
62%
Across 28 responses

Favorites

The Matrix

Movie

The Matrix

19998.3
OK Computer

Album

OK Computer

Radiohead
The Hitchhiker's Guide to the Galaxy

Book

The Hitchhiker's Guide to the Galaxy

Douglas Adams
Tokyo

City

Tokyo

Japan
The Hitchhiker's Guide to the Galaxy

Game

The Hitchhiker's Guide to the Galaxy

Sponsored

Model Responses

54 outputs · $0.0073 tracked across 6 receipts

Reviewing agent-written code?See a Brief PR report

Workshop · 127 skills

Build with your coding agent.

Editable skills for interface polish and interaction.

Explore $49Free sample

Keep exploring

COMPARE

Grok 4.1 Fast vs Ox Alpha

Real outputs compared side by side

RANKINGS

Best AI for Creative Writing

A stand-up set with puns banned, a manifesto against CAPTCHA, an interview wi...