Flickleaf processes selected page text, pasted text, and PDFs locally. It does not transmit document content, filenames, browsing history, preferences, identifiers, or usage analytics to the developer or a third party. PDF.js, its worker, fonts, and character maps are included in the extension package.

Only reading preferences (pace, pace limits, scroll mode, and theme) are saved in browser-local extension storage, not browser sync. Document text and PDF bytes remain in the current tab memory. Reopening the reader on the same page can retain the current position for that page session; refreshing or closing the page clears it. No persistent reading history is created. Reset preferences to remove saved settings. Private browsing does not write preferences or reading data to persistent storage.

Opening the separate website or GitHub sends ordinary website requests to those services. The website hosting provider can run browser security checks. Those services are separate from local extension parsing; Flickleaf does not attach a PDF or its extracted text to those requests.