Reviews of Lean Library

By: Lean Library Add-on

List of user reviews and ratings for Lean Library

Total ratings

2.70 (Rating count: 67)

Receive review notifications

Get notified when new reviews are posted so you can respond quickly.

See reviews on Firefox Add-ons Store

View and respond to reviews directly on the store page.

Visit

Review summary

Users find Lean Library very useful for accessing university-licensed papers, but many report severe performance and stability problems. Common complaints: it slows or freezes browsing, runs on non-academic sites with unreliable disable controls, breaks some websites or other extensions, and has a clunkier, more intrusive UI than alternatives like Sciwheel.

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.

Upgrade to see all 74 reviews

User Reviews

Recent rating average: 1.40

All time rating average: 2.70

Upgrade to see all 74 reviews

31% (23)

Date	Author	Comment
2026-06-05	ch*****	The extension doesn't work on Windows and doesn't even open on Linux. Sent detailed error reports, never heard back. (The only way it still kinda works is via the old sciwheel extension on Chrome, but there's probably a good chance this will die, too.) SAGE really murdered this once great product. Now I have to switch to something else and lose all of my anntoations. 😭 I hate these careless business people.
The extension doesn't work on Windows and doesn't even open on Linux. Sent detailed error reports, never heard back. (The only way it still kinda works is via the old sciwheel extension on Chrome, but there's probably a good chance this will die, too.) SAGE really murdered this once great product. Now I have to switch to something else and lose all of my anntoations. 😭 I hate these careless business people.
2026-05-21	an*****	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.
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.
2025-09-08	Ja*****	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.
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.
2025-09-06	Ju*****	I almost gave this 1 star, because while LeanLibrary works well when it actually functions, the overall experience is frustrating. The add-on causes extremely long loading times, sometimes to the point where pages just break after a few minutes. I do see the potential here, if these performance issues get resolved, this could easily be a 4/5 add-on. I also noticed the new feature that’s supposed to prevent it from running on non-library sites, but it doesn’t seem to work properly. It still loads on LinkedIn, social media, and entertainment sites where it shouldn’t. Lots of promise, but at the moment it’s more hassle than help.
I almost gave this 1 star, because while LeanLibrary works well when it actually functions, the overall experience is frustrating. The add-on causes extremely long loading times, sometimes to the point where pages just break after a few minutes. I do see the potential here, if these performance issues get resolved, this could easily be a 4/5 add-on. I also noticed the new feature that’s supposed to prevent it from running on non-library sites, but it doesn’t seem to work properly. It still loads on LinkedIn, social media, and entertainment sites where it shouldn’t. Lots of promise, but at the moment it’s more hassle than help.
2025-09-03	Ka*****	It's great at finding versions of papers that I can access through my university library account making it a very useful tool when researching. However it slows other sites down and often causes them to freeze so has to be kept uninstalled when not in use. Please fix this issue. I can't just pause it when not in use as it still slows down sites, please fix this.
It's great at finding versions of papers that I can access through my university library account making it a very useful tool when researching. However it slows other sites down and often causes them to freeze so has to be kept uninstalled when not in use. Please fix this issue. I can't just pause it when not in use as it still slows down sites, please fix this.
2025-09-02	pd*****	Doesn't seem to find any of the articles on the page. Slows Github and Youtube to an absolute crawl. The extension it replaced, Sciwheel, did one thing and did it very well-- this tries to do more and accomplishes nothing, while slowing down everything else. Really bad start of the rebrand, folks.
Doesn't seem to find any of the articles on the page. Slows Github and Youtube to an absolute crawl. The extension it replaced, Sciwheel, did one thing and did it very well-- this tries to do more and accomplishes nothing, while slowing down everything else. Really bad start of the rebrand, folks.
2025-08-18	Fi*****	Not a great extension, at best it merits 3/5 starts. HOWEVER it slows down every single website, sometimes freezing my entire PC for some absurd reason. I'd rather have a bookmarklet than this. From reading the developer responses to other reviews, they have been aware of the issues and bloat of the add-on for years yet have not actually fixed these things. It really feels like they got the product working and now are just cruising doing the bare minimum while reaping whatever money universities pay them.
Not a great extension, at best it merits 3/5 starts. HOWEVER it slows down every single website, sometimes freezing my entire PC for some absurd reason. I'd rather have a bookmarklet than this. From reading the developer responses to other reviews, they have been aware of the issues and bloat of the add-on for years yet have not actually fixed these things. It really feels like they got the product working and now are just cruising doing the bare minimum while reaping whatever money universities pay them.
2025-08-16	St*****

2025-08-14	Fi*****	Compared to the Sciwheel extension, this one is much more clunky and non-intuitive: it takes more clicks to save a citation, and it even took me a while to figure out how to save the citation in the first place. The number one thing I want from the extension is to save a citation. Nothing else. I don't want a pop up with the home page, I don't want to see statistics, I don't want hard-to-remove overlays that occlude content on the webpage. I just want to save citations so that I can write my research papers. Sciwheel did that. Lean Library gets in the way, which is frustrating. Moreover, I'm starting to encounter issues in various websites (not related to research) where Firefox hangs for a moment and an information bar pops up saying that Lean Library is slowing down Firefox. I removed Lean Library and will continue using the Sciwheel extension as long as it still works.
Compared to the Sciwheel extension, this one is much more clunky and non-intuitive: it takes more clicks to save a citation, and it even took me a while to figure out how to save the citation in the first place. The number one thing I want from the extension is to save a citation. Nothing else. I don't want a pop up with the home page, I don't want to see statistics, I don't want hard-to-remove overlays that occlude content on the webpage. I just want to save citations so that I can write my research papers. Sciwheel did that. Lean Library gets in the way, which is frustrating. Moreover, I'm starting to encounter issues in various websites (not related to research) where Firefox hangs for a moment and an information bar pops up saying that Lean Library is slowing down Firefox. I removed Lean Library and will continue using the Sciwheel extension as long as it still works.
2025-04-29	Ku*****	It's buggy, and it breaks some websites like: search dot nixos dot org
It's buggy, and it breaks some websites like: search dot nixos dot org