Is EpubPup - EPUB Reader Safe? — Extension Safety Profile

The extension requests access to all URLs () and the declarativeNetRequest API. This combination allows it to observe and modify network requests on any website you visit. For an EPUB reader, this is broader than typically necessary; many similar tools only need access to downloaded files or specific file types. The storage permission is common for saving settings and local reading material.

Users of e-book readers should be aware that broad host permissions can in theory be used to track browsing habits or inject content into web pages, even if the developer's stated purpose is handling EPUB links from various sources. While manifest V3 imposes more restrictions on network modification than previous versions, it remains important to grant such access only to extensions you trust. A careful user might consider whether a reader that processes local files truly needs to run on every website.

The fact sheet’s dimensions show a strong Data & Privacy score (83%), indicating developer-declared commitments not to sell data or use it for unrelated purposes. In contrast, the weakest area is Maintenance & Ownership (30%), which points to limited transparency about the publisher or potential infrequent updates. Coupled with generally positive user ratings, this suggests the extension may function well currently, but the long-term reliability and support should be weighed when choosing any tool that handles your browsing and reading activity.