What can be repaired
Most damaged PDFs are not ruined, just confusing for PDF readers. A broken index that says where each part of the file starts, stray bytes added by an email program, missing end markers and downloads that stopped early are all fixed by rebuilding the file from the pieces that are still there. Pages that are complete come back exactly as they were, with sharp, selectable text.
When a page cannot be saved
If part of a page is missing from the file, nothing can bring that part back. When a page still will not draw after the rebuild, the tool can keep a picture of whatever is readable instead of dropping the page. Each step is listed in the report, so you know which pages were rebuilt and how.
Privacy
The repair happens in your browser. Your PDF is never uploaded, and the repaired copy is saved straight to your device.