Zotero Connector and Safari 13+
Safari 13, released in September 2019, changed the way Safari extensions work, breaking the previous Zotero Connector for Safari that existed for many years.
A beta version of the Zotero Connector for Safari 13 and up is available as part of the beta version of the Zotero app rather than as a standalone extension. After running the Zotero beta once, the Zotero Connector will appear in the Extensions pane of the Safari preferences, where you'll need to enable it.
Due to an Apple bug, there's currently an issue where you may need to delete the Zotero beta app from Applications and redownload it after an app update to restore the Zotero Connector functionality in Safari. It may also be necessary to restart your computer in between deleting the app and redownloading. Note that you can continue to use the production version of Zotero on a daily basis if you so choose — the beta app simply needs to be installed in Applications (e.g., as “Zotero Beta”).
Safari 14, released in September 2020, added compatibility with the browser extensions supported by Chrome, Firefox, and other browsers, but the functionality is still buggy and incomplete. We've reported the bugs to Apple and hope to be able to again offer a stable version of the Zotero Connector for Safari as soon as those are fixed.
Follow @zotero on Twitter for updates.
While Zotero has offered a Zotero Connector for Safari for many years, in Safari 13 Apple discontinued support for the original type of Safari extension, causing the Zotero Connector and many other extensions to no longer work.
These Safari extensions, which worked similarly to extensions for Chrome and Firefox, were discontinued in favor of Safari App Extensions, a much more limited type of extension that must be distributed as part of a Mac app.
We invested significant resources building a Safari App Extension version of the Zotero Connector, but due to what we believe to be a bug in macOS, Zotero app updates can cause the extension to become permanently disabled in Safari, requiring the Zotero app to be deleted from Applications and reinstalled. While the extension is fully usable, because of this bug the new extension will remain available only as part of the Zotero beta.
Due to this problem and the general limitations of Safari App Extensions, for the best Zotero experience you may wish to use the Zotero Connector for Chrome or Firefox instead. Chrome and Firefox provide powerful extension frameworks that allow us to offer advanced functionality such as automatic proxy detection and automatic RIS/BibTeX import, features that weren't possible in Safari even before Apple further restricted what Safari extensions can do.
Note that Zotero is, to our knowledge, the only tool of its kind that has offered a dedicated extension for Safari instead of a much more limited bookmarklet. While Zotero offers a bookmarklet as well, the “Intelligent Tracking Prevention” in the latest versions of Safari can prevent the bookmarklet from working properly as it does in other browsers, so the bookmarklet may not serve as a suitable alternative at this time.
Safari 14 finally added support for the WebExtensions framework used by Chrome, Firefox, and other browsers, but the support is unfortunately still buggy and incomplete. We plan to offer a version of the standard Zotero Connector for Safari as soon as those bugs are fixed.