Frequently Asked Questions

My name is Claus Wolf and I have successfully developed and deployed PHP & JavaScript based applications for libraries for the last 7+ years. I will be the first to admit that I am not a great developer, but I have the pleasure to know that my apps are used by hundreds of institutions – although they wouldn’t know 😉

These days I work for a company operating in the “library space”, but this application is my hobby project and as such isn’t affiliated with my employer.

To be honest, I simply wanted to have a play to learn how a Safari App Extension would work. The development documentation is a bit light and I needed a real project to truly learn stuff. When I came across the rather useful Unpaywall API and their Google Chrome & Firefox extension, I was a bit sad that it wasn’t available for Safari. I quickly realized that I could build a super simple clone and make it available for free… Free is the right price, as the extension itself doesn’t do much and all the magic comes from the excellent unpaywall.org service.

I created the iOS App, since I felt a bit sorry that all the Open Access goodness was for desktop users only and just like with the Safari App Extension, I wanted to learn how a Safari Action Extension and Share Extension should be programmed. It’s fun to learn new things…

I created a document with test cases and their expected outcome, every release is tested against that document. You can access it here…

English & German

Please contact me, if you would like to help translate the app into more languages

Unpaywall.org covers > 46 million Open Access documents [27 December 2022], but there obviously are many more. The App will also check core.ac.uk Discovery and thus will have covered most sources available. Lastly, if you enable it, you can use OpenAccessButton.org to ask the author to make their work avaialble by posting it online in a legal and copyright compliant way.

Maybe your document just isn’t known, yet? Try searching BASE, core.ac.uk, DOAJ or Google Scholar, or speak to your library’s info desk. Library staff are oustanding at finding content and if there is no Open Access, they might be able to help you with an Inter Library Loan for less than what the publisher is asking for.

Another option is that the extension could not extract a DOI on the page. I am trying to be quick and nimble and thus look for certain meta-tags on the page, rather than look at all the content with a regular expression.
macOS Users: If you are ever in doubt, open the Developer Console (⌥+⌘+i) – I “print” a few bits there quite clearly 🙂

Sometimes you are at an Open Access location, but unpaywall.org reports a different location. Open Access is great, but often has more than one place to access a document.

Sometimes the code that follows the link gets to one place and stops and then “sees” two different domains, for example “linkinghub.elsevier.com” vs “www.sciencedirect.com”

Unpaywall.org is fast, but the code that follows all the redirects to determine, whether we are at the “final” location, depends on your internet speed and the number of redirects and the speed at which those servers respond.

You really shouldn’t trust anyone on the internet. If you know how to read a little JS and Swift, please review the macOS code on GitHub – it ain’t rocket science! You probably will want to check on these two files first:

The source code for the iOS app can be found here

Safari App Extensions and iOS Apps are pretty great and have a lot of solid features to protect your privacy, but in the end you need to decide, whether you wish to trust the extension or not. At the time of writing nothing in the code actively logs you or your browsing behavior. To make it obvious the extension does stuff, the toolbar icon will change, while the extension is active. The iOS App makes even fewer calls.

Some really solid advice for anything on the internet is: follow the money. If you don’t pay for something, you are likely the product.

  • The advice is right, yet I am doing this as a hobby, so the truth is: I am NOT making any money through the app
  • Like yourself, I have a full-time job that pays the bills. It is a pretty fun job and it pays reasonably well, so I don’t need the app to make money
  • The app wouldn’t work without unpaywall.org, so I feel that charging even a dollar would be unfair
  • If you don’t pay, I don’t owe you anything either. Thus, if you find a bug, report it – but no guarantees.
  • My wife said it was ok for me to spend €99 / year for the developer account. She loves me and thus doesn’t realize that I shouldn’t be trusted with money. If you don’t tell her, I won’t either.
  • Maybe you do want to send me a few dollars, just to say thank you? In that case, I suggest you give it someone, who needs it more. If you truly can’t think of anyone, click this link for a great organization, which will do wonderful work with your money (but they need more than a dollar at a time).

This is an old FAQ, but since you might have gotten here through otzberg.net – let me answer it anyway.

Otzberg is the name of the “mountain” overlooking the village in which I live.

When I lived in the US (a great many years ago) I started the habit of using this as my screen name on various services. When the opportunity arose I licensed otzberg.net and the rest is history.

Wikipedia has a pretty extensive article in German and English, check it out 🙂

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