What is the difference between xAI: Grok 4 Fast (free) and Horizon Alpha?

xAI: Grok 4 Fast (free) is developed by xAI while Horizon Alpha is developed by OpenRouter. xAI: Grok 4 Fast (free) has a 2.0M token context window vs Horizon Alpha's 256K. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, xAI: Grok 4 Fast (free) or Horizon Alpha?

It depends on your use case. xAI: Grok 4 Fast (free) and Horizon Alpha 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 xAI: Grok 4 Fast (free) cost compared to Horizon Alpha?

xAI: Grok 4 Fast (free) costs $0/M input tokens and Horizon Alpha costs $0/M input tokens. Horizon Alpha is $0.00/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 Horizon Alpha on Rival?

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

xAI: Grok 4 Fast (free) is developed by xAI while Horizon Alpha is developed by OpenRouter. xAI: Grok 4 Fast (free) has a 2.0M token context window vs Horizon Alpha's 256K. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, xAI: Grok 4 Fast (free) or Horizon Alpha?

It depends on your use case. xAI: Grok 4 Fast (free) and Horizon Alpha 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 xAI: Grok 4 Fast (free) cost compared to Horizon Alpha?

xAI: Grok 4 Fast (free) costs $0/M input tokens and Horizon Alpha costs $0/M input tokens. Horizon Alpha is $0.00/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 Horizon Alpha on Rival?

This page shows a side-by-side comparison of xAI: Grok 4 Fast (free) and Horizon Alpha 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 Horizon Alpha: Which Is Better?

Updated Sep 2025

Our Verdict

xAI: Grok 4 Fast (free)

Horizon AlphaRunner-up

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

Too close to call

API pricing

Cost per 1M tokens

xAI: Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Horizon Alpha

Input

$0.000

Output

$0.000

Writing DNA

Style Comparison

Similarity

68%

xAI: Grok 4 Fast (free) uses 138.0x more bold

xAI: Grok 4 Fast (free)

Horizon Alpha

65%Vocabulary65%

13wSentence Length14w

0.56Hedging0.22

1.4Bold0.0

2.5Lists3.5

0.00Emoji0.00

1.58Headings0.00

0.28Transitions0.12

Based on 14 + 14 text responses

Research

What we learned reading every model

xAI: Grok 4 Fast (free) and Horizon Alpha 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

xAI: Grok 4 Fast (free) vs MiniMax M3New provider

xAI: Grok 4 Fast (free) vs Claude Sonnet 4New provider

Horizon Alpha vs xAI: Grok 4Cross-provider

Updated Sep 2025

Our Verdict

xAI: Grok 4 Fast (free)

Horizon AlphaRunner-up

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

Too close to call

API pricing

Cost per 1M tokens

xAI: Grok 4 Fast (free)

Input

$0.000

Output

$0.000

Horizon Alpha

Input

$0.000

Output

$0.000

Writing DNA

Style Comparison

Similarity

68%

xAI: Grok 4 Fast (free) uses 138.0x more bold

xAI: Grok 4 Fast (free)

Horizon Alpha

65%Vocabulary65%

13wSentence Length14w

0.56Hedging0.22

1.4Bold0.0

2.5Lists3.5

0.00Emoji0.00

1.58Headings0.00

0.28Transitions0.12

Based on 14 + 14 text responses

Research

What we learned reading every model

xAI: Grok 4 Fast (free) and Horizon Alpha 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

xAI: Grok 4 Fast (free) vs MiniMax M3New provider

xAI: Grok 4 Fast (free) vs Claude Sonnet 4New provider

Horizon Alpha vs xAI: Grok 4Cross-provider