What Unpaywall is

On a scholarly article page, the extension checks Unpaywall's index of legally posted full texts, such as author manuscripts on university and government servers, and shows a green tab when a free copy exists. The developer says papers posted outside publisher permissions are excluded from the index.

Feature coverage

  • Automatic open-access lookup on article pages
  • Green tab linking to the free full text
  • Index of author-posted and repository copies

What stands out

  • Focused, single-purpose research tool
  • Large public footprint
  • Policy says the extension collects no personal data

Tradeoffs to know

  • No store update since January 2025
  • Middling rating for a free tool
  • Only finds legally posted versions

Permissions and privacy

Page access

To spot research articles, the extension checks the pages you visit and queries Unpaywall's index when it recognizes one. Restricting its site access in Chrome to the journal and publisher sites you use would keep the core lookup while limiting where it runs.

Data notes

The listing names location and website content, consistent with checking article pages against its index. Unpaywall's privacy policy says it does not collect personal information when you use the browser extension, though non-personal data such as IP addresses and browser type can reach its servers with lookups.

Pricing

Free browser extension. Pricing and plan limits change more often than store metadata, so use the linked developer page as the final check before subscribing.

Alternatives

AlternativeEndNote ClickAlternativeGoogle Scholar Button

Sources

We used the official Chrome Web Store listing and first-party developer material. Public metrics can change after the fact-check date.

  1. Chrome Web Store listing

    Rating, rating count, public users, version, update date, and publisher disclosures verified 2026-10-12.

  2. Unpaywall product documentation

    First-party product, feature, support, or project documentation used for workflow context.

  3. Extension Reviewer methodology

    How public claims, permissions, evidence, and tradeoffs are reviewed.

View in Chrome Web Store Developer site
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