What is the difference between xAI: Grok 4 Fast (free) and Inception: Mercury?

xAI: Grok 4 Fast (free) is developed by xAI while Inception: Mercury is developed by Inception. xAI: Grok 4 Fast (free) has a 2.0M token context window vs Inception: Mercury's 32K. You can compare their actual outputs across 35 challenges on Rival to see how they differ in practice.

Which is better, xAI: Grok 4 Fast (free) or Inception: Mercury?

It depends on your use case. xAI: Grok 4 Fast (free) and Inception: Mercury each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 35 challenges so you can judge which fits your needs best.

How much does xAI: Grok 4 Fast (free) cost compared to Inception: Mercury?

xAI: Grok 4 Fast (free) costs $0/M input tokens and Inception: Mercury costs $10/M input tokens. xAI: Grok 4 Fast (free) is $10.00/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 xAI: Grok 4 Fast (free) and Inception: Mercury on Rival?

This page shows a side-by-side comparison of xAI: Grok 4 Fast (free) and Inception: Mercury 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 xAI: Grok 4 Fast (free) and Inception: Mercury?

xAI: Grok 4 Fast (free) is developed by xAI while Inception: Mercury is developed by Inception. xAI: Grok 4 Fast (free) has a 2.0M token context window vs Inception: Mercury's 32K. You can compare their actual outputs across 35 challenges on Rival to see how they differ in practice.

Which is better, xAI: Grok 4 Fast (free) or Inception: Mercury?

It depends on your use case. xAI: Grok 4 Fast (free) and Inception: Mercury each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 35 challenges so you can judge which fits your needs best.

How much does xAI: Grok 4 Fast (free) cost compared to Inception: Mercury?

xAI: Grok 4 Fast (free) costs $0/M input tokens and Inception: Mercury costs $10/M input tokens. xAI: Grok 4 Fast (free) is $10.00/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 xAI: Grok 4 Fast (free) and Inception: Mercury on Rival?

This page shows a side-by-side comparison of xAI: Grok 4 Fast (free) and Inception: Mercury 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.

xAI: Grok 4 Fast (free) vs Inception: Mercury: Which Is Better?

Updated Sep 2025

Our Verdict

xAI: Grok 4 Fast (free)

Inception: MercuryRunner-up

No community votes yet. On paper, xAI: Grok 4 Fast (free) has the edge — bigger model tier, newer, bigger context window, major provider backing.

Slight edge

API pricing

Cost per 1M tokens

xAI: Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Inception: Mercury

Input

$10.00

Output

$10.00

Writing DNA

Style Comparison

Similarity

37%

Inception: Mercury uses 4.3x more emoji

xAI: Grok 4 Fast (free)

Inception: Mercury

65%Vocabulary55%

13wSentence Length40w

0.56Hedging0.39

1.4Bold4.9

2.5Lists3.8

0.00Emoji0.04

1.58Headings1.04

0.28Transitions0.03

Based on 14 + 17 text responses

Research

What we learned reading every model

xAI: Grok 4 Fast (free) and Inception: Mercury have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

Inception: Mercury vs MiniMax M3New provider

Inception: Mercury vs Claude Sonnet 4New provider

Inception: Mercury vs xAI: Grok 4Cross-provider

Updated Sep 2025

Our Verdict

xAI: Grok 4 Fast (free)

Inception: MercuryRunner-up

No community votes yet. On paper, xAI: Grok 4 Fast (free) has the edge — bigger model tier, newer, bigger context window, major provider backing.

Slight edge

API pricing

Cost per 1M tokens

xAI: Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Inception: Mercury

Input

$10.00

Output

$10.00

Writing DNA

Style Comparison

Similarity

37%

Inception: Mercury uses 4.3x more emoji

xAI: Grok 4 Fast (free)

Inception: Mercury

65%Vocabulary55%

13wSentence Length40w

0.56Hedging0.39

1.4Bold4.9

2.5Lists3.8

0.00Emoji0.04

1.58Headings1.04

0.28Transitions0.03

Based on 14 + 17 text responses

Research

What we learned reading every model

xAI: Grok 4 Fast (free) and Inception: Mercury have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

Inception: Mercury vs MiniMax M3New provider

Inception: Mercury vs Claude Sonnet 4New provider

Inception: Mercury vs xAI: Grok 4Cross-provider