Laguna S 2.1 (free) vs 
Riverflow V2 Fast
Laguna S 2.1 (free) has a larger context window than Riverflow V2 Fast (262K tokens vs 8K tokens).
Written rounds
1 promptBuy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.
Price and specs
Not enough votes to call it. On the specs, Laguna S 2.1 (free) has the edge: newer, bigger context window.
| Spec | Laguna S 2.1 (free) | Riverflow V2 Fast |
|---|---|---|
| Input price | Free | — |
| Output price | Free | — |
| Context window | 262K tokens | 8K tokens |
| Free API (OpenRouter) | Yes (1 provider) | No |
| Released | Jul 2026 | Feb 2026 |
| At 10M a month | $0 | not listed |
Input tokens at list price. No caching, no batch discount.
Where to run it
Laguna S 2.1 (free)1 host
Riverflow V2 Fast1 host
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Common questions
What is the difference between Laguna S 2.1 (free) and Riverflow V2 Fast?
Laguna S 2.1 (free) is developed by Poolside while Riverflow V2 Fast is developed by Sourceful. Laguna S 2.1 (free) has a 262K token context window vs Riverflow V2 Fast's 8K. You can compare their actual outputs across 1 challenges on Rival to see how they differ in practice.
Which is better, Laguna S 2.1 (free) or Riverflow V2 Fast?
It depends on your use case. Laguna S 2.1 (free) and Riverflow V2 Fast each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 1 challenges so you can judge which fits your needs best.
How can I compare Laguna S 2.1 (free) and Riverflow V2 Fast on Rival?
This page shows a side-by-side comparison of Laguna S 2.1 (free) and Riverflow V2 Fast 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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