Arena vs Undermind
Plans, free access, limits and intended use side by side, taken from each vendor’s own pages. No score and no winner: the facts show where the two differ.
Change tools
Free by the terms today, with no published price list
Deep literature search that reports its own coverage
- Free access
- Arena: Free access
- Undermind: Free access
- Paid from
- Arena: No fixed price listed
- Undermind: USD 75 per month
- Plans listed
- Arena: 1
- Undermind: 6
- Public API
- Arena: Not confirmed
- Undermind: Not confirmed
Where Arena and Undermind differ
- Pricing checkPrices not confirmed for Arena; prices confirmed for Undermind.
- PlansArena lists 1 plans and Undermind lists 6.
Head to head
Each value from the tool’s profile and the vendor’s own pages
| Arena | Fact | Undermind |
|---|---|---|
| Access and price | ||
| Free access available | Free accessSame | Free access availableFree · USD 0 |
| No fixed price listed | Lowest listed paid plan | USD 75 per monthPro (Industry) · or $60 per month billed annually |
| Free per Terms of Use; no price list | Pricing model | Free plan; Pro from $16 a month billed annually |
| 1 | Plans listedDiffers | 6 |
| Not confirmed | Public API | Not confirmed |
| Not confirmed | Card to start | Not confirmed |
| Not confirmed | Open source | Not confirmed |
| What it is for | ||
| Comparing AI model answers by voting, without a paid plan | Built for | Finding hard-to-locate papers on a specific research question |
| Research & sources | CategorySame | Research & sources |
| Platforms |
|
| Works with |
|
| How current | ||
| Profile sources checked | ||
| Prices not confirmed · Sep 30, 2026 | Pricing checkDiffers | Prices confirmed · Oct 11, 2026 |
Official source check for both tools. No hands-on testing and no score: “Differs” marks a documented difference, not a better tool.
Plans and prices
Arena
Prices not confirmed · Sep 30, 2026- Free access (per Terms of Use)Free of charge per the terms; no public price list
Undermind
Prices confirmed · Oct 11, 2026- FreeUSD 0
- Pro (Academic)USD 20 per monthor $16 per month billed annually
- Pro (Industry)USD 75 per monthor $60 per month billed annually
- Team (Academic)USD 18.70 per person per monthor $15 per person per month billed annually
- Team (Industry)USD 75 per person per monthor $60 per person per month billed annually
Show 1 more plan
- EnterpriseCustom
Strengths and limits
Arena
Strengths
- Free access per the terms: The terms state the service is currently free of charge and the credit help page describes a daily free balance.
- Method documented in public: The FAQ and help pages explain the voting model, anonymity and which modes affect rankings.
- Leaderboards need no login: Rankings and filters can be browsed without an account.
Limits to plan around
- No published price or credit size: The pricing URL shows a not-found page and the daily credit amount is not stated.
- Prompts are shared beyond Arena: Inputs go to third-party model providers, and conversations can feed de-identified public datasets.
- Terms allow future charges: The terms reserve the right to charge for the service or any feature.
Undermind
Strengths
- Free plan with agent access: The pricing section lists agent connections and shared workspaces at $0, with abstracts and metadata searched.
- Coverage is reported: The provider says the report summary states when a search has probably not found everything, so you can extend it.
- Full-text search on Pro: The FAQ says Pro adds search of the full texts of nearly all open-access and preprint papers.
Limits to plan around
- Unnumbered limits: Free has standard rate limits and Pro 10x higher limits, but no page gives the base numbers.
- Single source database: Search draws on Semantic Scholar; the FAQ says a specific paper may not be in it.
- No refunds: The refund policy calls charges non-refundable once a billing period has begun, except where required by law.
See both products
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Comparing tools from different categories is fine, and often useful — a writing assistant and a research tool solve different halves of the same job. The table will show you exactly where they diverge.
Questions about comparing tools
How does the comparison work?
Add two tools to the comparison tray from any tool card, then open this page. The table pulls each tool's verified plan details, platforms, strengths and limits from its profile, so both columns carry the same kind of evidence, with a separate source-check date for each tool.
Do you declare a winner?
No. The table sets two tools against each other on documented facts, not on a score. Which one wins depends on your task, your budget and your usage volume — three things we cannot see from here.
Why are some cells empty or marked unverified?
Because we could not confirm that detail on the vendor's own pages. Rather than filling the gap with a figure from elsewhere, we mark it and say why on the tool's profile.
Can I compare more than two tools?
Not at once. Two columns keep the differences readable and force a real decision. Remove either selected tool to replace it, or clear both to start a new pair.
Every figure in the table above comes from the linked profile, where the source and the verification date are listed. Browse all tools or read the editorial policy.