Is EpubPup - EPUB Reader Safe? — Extension Safety Profile

EpubPup requests the declarativeNetRequest and storage API permissions, along with host access to all URLs (). The storage permission is normal for saving book preferences and reading progress. However, declarativeNetRequest gives the extension the ability to modify or block network requests on any site you visit. For an EPUB reader, this power is unusually broad—most reading tools only need to open files or user-provided links, not inspect and alter all web traffic.

E-book extensions with full host access can potentially view the content of every webpage, not just book files. In this category, a cautious user should assess whether such wide permissions are truly necessary for the promised features. While fetching EPUBs from any URL might justify some host access, the ability to rewrite network requests introduces a higher level of influence over your browsing that deserves careful consideration.

According to the fact sheet, this extension’s strongest safety dimension is Community Reputation, reflecting a healthy rating and user base. Its weakest dimension is Maintenance & Ownership, which suggests potential concerns about update frequency or publisher transparency. This means the extension works well for many users today, but its long-term upkeep may be less certain, and users should keep that in mind when granting extensive permissions.