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  5. Grok 4 Fast (free)vsSolar Mini 4
Updated Sep 2026

Grok 4 Fast (free)vsSolar Mini 4

Grok 4 Fast (free) is cheaper than Solar Mini 4 at $0/M vs $0.05/M input tokens.

Grok 4 Fast (free) and Solar Mini 4 compared across 2 shared prompts
SpecGrok 4 Fast (free)Solar Mini 4
Input priceFree$0.05/M tokens
Output priceFree$0.2/M tokens
Context window2.0M tokens524K tokens
Free API (OpenRouter)NoNo
ReleasedSep 2025Sep 2026
Side by side

Same prompt, both answers

Opening lines from every prompt both answered. Formatting stripped, words untouched.

Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Grok 4 Fast (free)849 words
1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.
Read the full answer
Solar Mini 4669 words
Here is a simple, actionable 1-month plan designed for beginners. The focus is on consistency over intensity, meaning small, sustainable changes are better than drastic overhauls that are hard to maintain. The 3 Key Pillars Nutrition: Focus on adding good things rather than strictly restricting.
Read the full answer

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

Grok 4 Fast (free)240 words
Pantry Hero Pasta Primavera This simple, savory one-pot pasta dish transforms basic staples into a flavorful, garlicky tomato sauce that's comforting and ready in under 30 minutes.
Read the full answer
Solar Mini 4266 words
🌟 Golden Chickpea & Rice Skillet This comforting one-pot dish combines hearty chickpeas, tender rice, and a warm blend of spices. It's a perfect way to use up pantry staples for a quick, flavorful meal.
Read the full answer
Our Verdict
Grok 4 Fast (free)
Grok 4 Fast (free)
Solar Mini 4
Solar Mini 4Runner-up

Not enough votes to call it. On the specs, Grok 4 Fast (free) has the edge: bigger model tier, bigger context window, major provider backing.

Too close to call
API pricing

Cost per 1M tokens

Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Solar Mini 4
Input
$0.05
Output
$0.20
Where to run it

1 host

Grok 4 Fast (free)

No hosts listed on OpenRouter.

Solar Mini 41 host
HostInOutContextUptime
UUpstage$0.05 in·$0.20 out·524k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Grok 4 Fast (free) is developed by xAI while Solar Mini 4 is developed by Upstage. Grok 4 Fast (free) has a 2.0M token context window vs Solar Mini 4's 524K. You can compare their actual outputs across 2 challenges on Rival to see how they differ in practice.

It depends on your use case. Grok 4 Fast (free) and Solar Mini 4 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 2 challenges so you can judge which fits your needs best.

Grok 4 Fast (free) costs $0/M input tokens and Solar Mini 4 costs $0.05/M input tokens. Grok 4 Fast (free) is $0.05/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Grok 4 Fast (free) and Solar Mini 4 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.

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Model pages

Grok 4 Fast (free) logo
Grok 4 Fast (free)35 outputs, specs and price
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