What is the difference between Grok 4 Fast (free) and Kimi K3?

Grok 4 Fast (free) is developed by xAI while Kimi K3 is developed by Moonshot AI. Grok 4 Fast (free) has a 2.0M token context window vs Kimi K3's 1.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Kimi K3?

It depends on your use case. Grok 4 Fast (free) and Kimi K3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Kimi K3?

Grok 4 Fast (free) costs $0/M input tokens and Kimi K3 costs $3/M input tokens. Grok 4 Fast (free) is $3.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Grok 4 Fast (free) and Kimi K3 on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) and Kimi K3 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

What is the difference between Grok 4 Fast (free) and Kimi K3?

Grok 4 Fast (free) is developed by xAI while Kimi K3 is developed by Moonshot AI. Grok 4 Fast (free) has a 2.0M token context window vs Kimi K3's 1.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Kimi K3?

It depends on your use case. Grok 4 Fast (free) and Kimi K3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Kimi K3?

Grok 4 Fast (free) costs $0/M input tokens and Kimi K3 costs $3/M input tokens. Grok 4 Fast (free) is $3.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Grok 4 Fast (free) and Kimi K3 on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) and Kimi K3 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Grok 4 Fast (free) vs Kimi K3: Which Is Better?

Updated Jul 2026

Our Verdict

Grok 4 Fast (free)

Kimi K3

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

What do Grok 4 Fast (free) and Kimi K3 say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Kimi K3

Input

$3.00

Output

$15.00

Writing DNA

Style Comparison

Similarity

61%

Kimi K3 uses 77.9x more emoji

Grok 4 Fast (free)

Kimi K3

65%Vocabulary58%

13wSentence Length21w

0.56Hedging0.46

1.4Bold3.6

2.5Lists3.4

0.00Emoji0.78

1.58Headings0.89

0.28Transitions0.17

Based on 14 + 27 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Grok 4 Fast (free) vs Ox AlphaNew provider

Grok 4 Fast (free) vs MiniMax M3New provider

Grok 4 Fast (free) vs GPT-5New provider

Updated Jul 2026

Our Verdict

Grok 4 Fast (free)

Kimi K3

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call

What do Grok 4 Fast (free) and Kimi K3 say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Kimi K3

Input

$3.00

Output

$15.00

Writing DNA

Style Comparison

Similarity

61%

Kimi K3 uses 77.9x more emoji

Grok 4 Fast (free)

Kimi K3

65%Vocabulary58%

13wSentence Length21w

0.56Hedging0.46

1.4Bold3.6

2.5Lists3.4

0.00Emoji0.78

1.58Headings0.89

0.28Transitions0.17

Based on 14 + 27 text responses

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Grok 4 Fast (free) vs Ox AlphaNew provider

Grok 4 Fast (free) vs MiniMax M3New provider

Grok 4 Fast (free) vs GPT-5New provider