By: Lean Library
The Lean Library extension is a free tool which assists your library in delivering their services directly into your research workflow in more ways than one!
Features & Capabilities
User Growth & Download Statistics
- By:
- Lean Library
- Daily users:
- 10,168 -35
- Rating:
- 2.70 (67)
- Version:
- 2026.7.1 Last updated: 2026-05-12
- Version code:
- 6251488
- Creation date:
- 2017-02-22
- Risk:
- High risk impact High risk likelihood
- Permissions:
- Host permissions:
- http://*/*
- https://*/*
- <all_urls>
- http://*/*
- Content scripts matches:
- *
- <all_urls>
- *
- Size:
- 11.87MB
- Email:
- su*****@leanlibrary.com
- URLs:
- Website ,Privacy policy
- Full description:
- See detailed description
- Source:
- Firefox Add-ons Store
- Data ingested on:
- 2026-06-15
- Compare stats and ranking:
- Lean Library vs Leiden Search Assistant Plus
- Lean Library vs Open Access Helper
- Lean Library vs Library Extension
Ranking
# 770 ▲ 2
For Developers
Contact the developer
Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.
Permission Change History
2024-11-11: Version 2024.25.0 → 2024.26.4
Remove Permissions: webRequest
2024-01-30: Version 2023.30.0 → 2024.1.5
Add Permissions: webRequest
2023-10-09: Version 2023.25.2 → 2023.26.2
Remove Permissions: scripting
2023-08-29: Version 2023.4.1 → 2023.23.3
Add Host permissions: http://*/* https://*/* <all_urls>
Add Permissions: alarms activeTab scripting
Remove Permissions: webRequest http://*/* https://*/*
User Reviews
Pros
- Effectively finds versions of papers accessible through university library accounts, helping access paywalled academic content.
- Useful research tool/shortcut to institution resources — saves time when it works.
- Some users report reliable access to literature and easy institution sign-in when the extension loads properly.
Cons
- Severe performance problems: slows browsing, causes pages or the browser to hang or freeze.
- Always-on behavior and poor site controls — runs on non-academic sites, pops up where it shouldn’t, and disable switches are unreliable.
- Bugs and instability: breaks some websites and interferes with other extensions; can get stuck on loading or have login/selection issues.
- Clunky UI and feature bloat compared with predecessor (Sciwheel): saving citations takes more steps and overlays can be intrusive.
Recent reviews
The extension completely froze/refused to open after updates. Furthermore, the reference manager and annotation features were completely missing because my uni has subscribed to Lean Library, but they have not enabled Lean Library Workspace. This silently bricked the reference manager without any error messages.
The Solution:
Clean Reinstall: Fully uninstall and reinstall the extension (don't just update it) to clear the corrupted local cache and un-freeze the UI toolbar icon.
Add "Lean Library Open" as a "secondary Institute". This forces the reference manager features to activate alongside your university's proxy.
by ch*****, 2026-06-05
1) For a closed source extension that should have a very basic function you require too many permissions
2) Even after performance updates its still makes websites (especially websites that this extension has no business running on) extremely laggy even on a high performance PC with Gigabit network speed
3) I would never use this if my university didn't force it on me
4) sci-hub will always remain the most convenient and fastest option, but this extension does it job when sci-hub doesn't have what I'm looking for. But I always keep it disabled otherwise.
5) One serious suggestion would be to allow the user the option to manually trigger the extension on demand only, this will instantly solve the performance issues and privacy concerns. Keep the auto option for people how don't care
6) Privacy statements do not matter, even if you are acting in good faith, data leaks in case of attacks still happen.
Best way to protect your customers data is to never even store it.
by an*****, 2026-05-21
Spyware extension to replace a functional extension (sciwheel). This extension tracks all of your web browsing and shares and sells it to data brokers and other companies, including marketing agencies.
"Required permissions:
Access browser tabs
Access browser activity during navigation
Access your data for all websites"
'If the product is free, you are the product'. Wonder why everyone is complaining about the extension slowing down their browser? Maybe because its constantly scraping and recording everything you're doing..
There was a Q/A where they said they tried to put these concerns to rest, but their privacy statement says it all:
When We Share Your Information"
1) As Required by Law:
2) For Your Safety and Protection:
3) With Our Trusted Service Providers: We work with third-party service providers (e.g. cloud hosting, analytics, customer support platforms) who assist us in operating and improving our products. These providers are only allowed to use the information for the specific services we hire them for, act on our instructions, and are bound by strict contractual agreements to protect your data.
---- the wording is interesting here, "The providers are only allowed to use the information for the specific services we hire them for, act on our instructions..." This is intentionally vague and could be used for any reason...
4) In Business Changes: "If Technology from Sage (or a product line like Lean Library or Talis) is involved in a merger, acquisition, or sale of all or a portion of its assets, your information may be transferred as part of that transaction. You will be notified of any such change in ownership or use of your information."
---- As soon as the company changes hands, all your data belongs to someone else and its use has no limitations.
5) With Partners (Anonymised Data Only): We may disclose anonymised and aggregated data (data that cannot be linked back to you personally) with our partners or for marketing purposes. This helps us and our partners understand trends, improve access to academic materials, or enhance products without revealing your identity.
---- 1) True anonymisation is incredibly hard.. They collect device IDs, IP addresses, browsing patters, demographic information, etc., They do not outline how they will anonymize the data. When your name, birthday, or other personal or identifying information is collected, they do not specify how they will ensure *all instances of identifiable information* will be scrubbed before data is shared. Example: if you log in to LinkedIn and click on your profile, the new tab is named your full name and this is collected by them being able to 'Access browser tabs'. 2) They also say that the data, 'cannot be linked back to you personally' (which is false) and it can be linked to your devices which can be linked back to you. A single other dataset and this can be linked to all other existing data on you 3) "FOR MARKETING PURPOSES". This one is self explanatory, monetary incentive. 4) They do not say who the partners are.. could be anyone. Could be tech firms, ad firms, analytic firms 5) Once the data are shared with partners, you cannot have them deleted.
by Ja*****, 2025-09-08
Is Lean Library Safe?
Risk impact
Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.
Lean Library requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.
Risk impact analysis details
- Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
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- High ****** ********* ** * ****** ******** ******** ********** * ******* ******* *****
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Risk likelihood
Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.
Lean Library may not be trust-worthy. Avoid installing if possible unless you really trust this publisher.
Risk likelihood analysis details
- Medium This extension was updated in the past 3 months. New updates may not be stable or safe.
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- Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
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