What is the difference between Gemini 3.5 Flash and Grok 4 Fast (free)?

Gemini 3.5 Flash is developed by Google AI while Grok 4 Fast (free) is developed by xAI. Gemini 3.5 Flash has a 1.0M token context window vs Grok 4 Fast (free)'s 2.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.5 Flash or Grok 4 Fast (free)?

It depends on your use case. Gemini 3.5 Flash and Grok 4 Fast (free) 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 Gemini 3.5 Flash cost compared to Grok 4 Fast (free)?

Gemini 3.5 Flash costs $1.5/M input tokens and Grok 4 Fast (free) costs $0/M input tokens. Grok 4 Fast (free) is $1.50/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 Gemini 3.5 Flash and Grok 4 Fast (free) on Rival?

This page shows a side-by-side comparison of Gemini 3.5 Flash and Grok 4 Fast (free) 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 Gemini 3.5 Flash and Grok 4 Fast (free)?

Gemini 3.5 Flash is developed by Google AI while Grok 4 Fast (free) is developed by xAI. Gemini 3.5 Flash has a 1.0M token context window vs Grok 4 Fast (free)'s 2.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Gemini 3.5 Flash or Grok 4 Fast (free)?

It depends on your use case. Gemini 3.5 Flash and Grok 4 Fast (free) 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 Gemini 3.5 Flash cost compared to Grok 4 Fast (free)?

Gemini 3.5 Flash costs $1.5/M input tokens and Grok 4 Fast (free) costs $0/M input tokens. Grok 4 Fast (free) is $1.50/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 Gemini 3.5 Flash and Grok 4 Fast (free) on Rival?

This page shows a side-by-side comparison of Gemini 3.5 Flash and Grok 4 Fast (free) 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.

Gemini 3.5 Flash vs Grok 4 Fast (free): Which Is Better?

Updated May 2026

Our Verdict

Gemini 3.5 Flash

Grok 4 Fast (free)

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 Gemini 3.5 Flash and Grok 4 Fast (free) say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

Gemini 3.5 Flash

Input

$1.50

Output

$9.00

Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Writing DNA

Style Comparison

Similarity

55%

Grok 4 Fast (free) uses 3.6x more hedging

Gemini 3.5 Flash

Grok 4 Fast (free)

59%Vocabulary65%

18wSentence Length13w

0.16Hedging0.56

4.4Bold1.4

3.0Lists2.5

0.00Emoji0.00

0.89Headings1.58

0.11Transitions0.28

Based on 27 + 14 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 Muse Spark 1.1New provider

Updated May 2026

Our Verdict

Gemini 3.5 Flash

Grok 4 Fast (free)

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 Gemini 3.5 Flash and Grok 4 Fast (free) say about your brand?

10 models, one question, verbatim receipts.

or peek at a demo: Notion Linear Vercel

API pricing

Cost per 1M tokens

Gemini 3.5 Flash

Input

$1.50

Output

$9.00

Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Writing DNA

Style Comparison

Similarity

55%

Grok 4 Fast (free) uses 3.6x more hedging

Gemini 3.5 Flash

Grok 4 Fast (free)

59%Vocabulary65%

18wSentence Length13w

0.16Hedging0.56

4.4Bold1.4

3.0Lists2.5

0.00Emoji0.00

0.89Headings1.58

0.11Transitions0.28

Based on 27 + 14 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 Muse Spark 1.1New provider