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Unpaywall

Unpaywall is a free Chrome and Firefox extension and API that finds legal, free copies of paywalled research papers for students and researchers.

Our take: Unpaywall does one job well: when you land on a paywalled paper, it tells you if a legal free copy exists and links to it.

Best forLegal free research papers
ReviewedPricing: Free
7.7 out of 105 criteria · see breakdown
Try UnpaywallFree extension and API

Unpaywall is a free browser extension and API that finds legal, free-to-read copies of paywalled research papers. It suits students, researchers and libraries, and the extension and API cost nothing. The OpenAlex team maintains it and says it is not being retired.

Unpaywall now runs on OpenAlex

Unpaywall moved onto the OpenAlex database in late 2025 and is maintained by the OpenAlex team. Its help center says the DOI lookup API, browser extension and Data Feed are unchanged and staying.

The article search on unpaywall.org has been retired. To search for papers by topic, the team points users to OpenAlex.

Checked October 4, 2026
The bottom line

Install it if you read research papers; it is free and legal.

Our score

Reviewed by the Conversion Gems editorial team. Hover a facet to focus it; click to pin.Tap a facet to focus it.

What it is, and why we rate it

One line each. Open a row for detail.

What it really isA free browser extension and API that find legal open-access copies of scholarly articles.
Our takeUnpaywall does one job well: when you land on a paywalled paper, it tells you if a legal free copy exists and links to it.
Its data now runs on OpenAlex, and the team says the extension and API are staying, which matters after the article search was retired. The extensions themselves have not been updated in a while, January 2025 on Chrome and 2021 on Firefox, so expect a plain tool rather than new features. It cannot conjure a copy that no one has posted.
Why we rate itIt gives anyone a free, legal route to millions of open-access papers in one click.
The catchIt only finds copies that exist, and the extensions see infrequent updates.

Best / not good for

Best for
  • Students and researchers hitting paywalls
  • Libraries adding open-access links
  • Developers checking open-access status by DOI
Not good for
  • Papers with no free version anywhere
  • Searching for papers by topic (use OpenAlex)
  • Non-DOI content
Trade-offs

Friction report

Trade-offs to know before signing up.

  1. Time to value
    Instant: install the extension and open any article page.
  2. Scale breakpoint
    Bulk data needs move you to the paid Data Feed or the OpenAlex API.
  3. Walled garden
    None: open data and an MIT-licensed Firefox add-on.
Still a fit?
If none of these block you, start on the free plan.
Try Unpaywall

Unpaywall products and cost

ProductWhat it doesCost
Browser extensionGreen tab on article pages when a legal free copy exists (Chrome; Firefox desktop and Android)Free
REST APIOpen-access status and best location for any Crossref DOIFree
Simple Query ToolChecks up to 1,000 DOIs and emails the resultsFree
Data FeedDaily change files in the Unpaywall record formatSubscription (price not published)

From Unpaywall's product pages and the OpenAlex help center, checked 4 October 2026.

Frequently Asked Questions

Is Unpaywall free?

Yes. The browser extension and the DOI lookup API are free. Only the Data Feed, which delivers daily data updates to institutions, is a subscription (checked 4 October 2026).

Is Unpaywall legal?

Yes. It links only to copies that are free to read legally, such as author-posted manuscripts on university and government servers, a practice known as Green Open Access. It does not bypass paywalls.

Is Unpaywall shutting down?

No. The OpenAlex team, which maintains it, says it is not retiring Unpaywall and that the API, extension and Data Feed are staying. Only the article search on unpaywall.org was retired, with OpenAlex recommended instead.

Does Unpaywall work on Android?

The Firefox add-on supports Firefox for Android. The Chrome extension is for desktop Chrome.

How does the Unpaywall extension work?

When you open a scholarly article, it checks its database for a free legal copy. If one exists, a green tab appears on the side of the page that links to the full text.

What can I use instead of Unpaywall?

For searching papers, the Unpaywall team points to OpenAlex. In our directory, Perplexity helps with cited answers, and Paper Digest and Afforai help you read and summarise papers once you have them.

Unpaywall alternatives

Other research tools in our directory:

Showing 1–3 of 3
Sources checked October 4, 2026: Unpaywall homepage, Unpaywall browser extension, OpenAlex help: Unpaywall, Unpaywall article search retired, Unpaywall on the Chrome Web Store, Unpaywall on Firefox Add-ons.

Conversion Gems independently reviews every tool.

Tags

#OpenAccess#Research#BrowserExtension

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